JP2000182505A - Electric leakage safety device and hot-water supplying device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric leakage safety device, cutting off the supply of power from a main power output terminal at the time of leakage detection while continuously performing the supply of power from other power output terminals than the main power output terminal. SOLUTION: In this electric leakage safety device 1 comprising, at least, a power input terminal 2 connected to a power supply, a main power output terminal 3 connected to a load, a leak detection circuit 4 for detecting a leak in a cable way on the side of the load Z connected to the main power output terminal 3, and a relay 5 that works when the leak is detected in the leak detection circuit 4, the relay 5 comprises a two-contact type relay and is provided with an auxiliary power output terminal 6 on the side of contacts (b) thereof put to connection at the time of leak detection. Stand-by power output terminals 7, 8 are provided on, and connected in parallel with, the main power output terminal 3 and the auxiliary power output terminal 6, respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ground fault safety device and a hot water supply device, and more particularly, to a ground fault safety device (leakage breaker) incorporated in an electric device such as a hot water supply device.

[0002]

2. Description of the Related Art Conventionally, in equipment that uses water, such as a hot water supply device, a circulating pump for a bath, a water flow sensor, a heat exchanger, piping around water, etc. are prevented from freezing in winter when the temperature drops. One provided with a freeze prevention heater is provided.

Various types of such anti-freezing heaters are provided, but as a relatively simple configuration, for example, a heater composed of a heating wire is wound around the outer periphery of a pipe around water to lower the outside air temperature. It is known to heat the heater with the above, and in recent hot water heaters,
There is also provided one in which the on / off operation of such a freeze prevention heater is controlled by a control unit of a water heater.

[0004] On the other hand, in the field of household equipment including a hot water supply device, an earth leakage safety device which operates when an electric leakage is detected due to, for example, damage to an insulation part of the appliance and shuts off power supply to the appliance is provided. Various electric devices are provided.

FIG. 4 shows a schematic configuration of such an earth leakage safety device. The earth leakage safety device a shown in FIG. 4 has a conventionally well-known configuration, and has an input terminal b connected to a power supply E such as a commercial power supply, and an output terminal c connected to a load Z.
And a leakage detecting circuit d disposed between the input terminal b and the output terminal c, and a relay e having normally closed contacts. The leakage detection circuit d detects a leakage current (ground fault current) from the difference between the forward current i ₁ to the load Z and the return current i ₂ from the load Z, and when the leakage current exceeds a predetermined value. The power supply to the load Z is cut off by opening the contact point of the relay e, and a hot water supply device having such a leakage safety device is also provided.

[0006]

However, in the hot water supply device provided with such an electric leakage safety device, since the relay e used in the electric leakage safety device has one contact, there are the following problems. The improvement was desired.

That is, when the leakage safety device a is provided on the power supply path to the hot water supply device, if a short circuit occurs in a part of the electric system of the hot water supply device due to, for example, biting of electric wiring (line damage) or the like, The contact of the relay e is opened to cut off the power supply to the entire hot water supply device. Therefore, as shown in FIG. 5, when the power supply circuit of the freezing prevention heater is connected to the short circuit prevention device a, the power supply to the freezing prevention heater is cut off by the detection of the short circuit, and as a result, the temperature decreases. In such a case, the freeze prevention heater does not operate.

In order to avoid such a situation,
It is conceivable that the power supply circuit of the freeze prevention heater is a separate circuit that does not pass through the earth leakage safety device a. However, in this case, if the leakage prevention of the freeze prevention heater itself cannot be performed, it is not possible to detect the problem. On the other hand, even if such a configuration is adopted for the kari, in recent hot water heaters,
Since a relay f for controlling the ON / OFF operation of the freeze prevention heater (controlled by the control unit of the hot water supply device not shown) is provided in the power supply circuit of the freeze prevention heater (see FIG. 5), such a configuration is provided. In order to operate the freeze prevention heater normally, not only the power supply circuit of the freeze prevention heater but also the power supply circuit of the control unit of the hot water supply device must be configured as a separate circuit, and as a result, its realization is practical. It wasn't.

In addition, as described above, in the case where the earth leakage safety device is built in the hot water supply device, the built-in earth leakage safety device is used as a so-called dedicated product which does not detect the earth leakage of other equipment. When retrofitting the anti-freezing heater or other attached electric equipment, there is a problem that a separate earth leakage safety device must be prepared for the anti-freezing heater.

The present invention has been made in view of the above-mentioned conventional problems, and has as its object to cut off power supply from a main power supply output terminal at the time of detecting leakage, and to connect the power supply output terminal with the power supply output terminal. The main object of the present invention is to provide a leakage safety device capable of continuously supplying power from another power output terminal.

[0011]

To achieve the above object, an earth leakage safety device according to claim 1 of the present invention comprises at least a power supply input terminal connected to a power supply and a main power supply connected to a load. An output terminal, a leakage detection circuit that detects leakage of a load-side electric circuit connected to the main power output terminal,
A leakage protection device comprising: a relay that operates when a leakage is detected in the leakage detection circuit, wherein the relay is a two-contact type relay, and an auxiliary power supply is provided at a contact connected when a leakage is detected. An output terminal is provided.

That is, according to the first aspect of the present invention, a one-contact type relay used in a conventional earth leakage safety device is changed to a two-contact type relay, and a new power output is provided on the added contact side. A terminal (auxiliary power supply output terminal) is provided. Therefore, in this earth leakage safety device, when an earth leakage in the electric circuit of the load connected to the main power output terminal is detected in the earth leakage detection circuit, the contact of the relay is switched to the newly added auxiliary power output terminal side, As a result, while power supply to the main power output terminal side is cut off, power output can be obtained from the auxiliary power output terminal side.

Therefore, according to this earth leakage safety device, a circuit which requires power supply even when the earth leakage is detected (for example, a power supply circuit for a freeze prevention heater in a hot water supply device).
By connecting a circuit requiring constant power supply to the above-mentioned auxiliary power supply output terminal in the device provided with the above, power can be stably supplied to the circuit even after leakage detection.

Further, the earth leakage safety device according to a second aspect of the present invention is configured such that the auxiliary power supply output terminal is in the form of a metal fitting for electrically connecting a load wire connected to this terminal by screwing. It is characterized by having.

That is, the second aspect of the present invention employs a so-called screw-type metal fitting, which has been widely used for electric wiring, as the form of the auxiliary power supply output terminal. Thereby, when a load is connected to the auxiliary power supply output terminal, the screw is tightened and fixed while the conductive wire portion is in contact with the metal fitting while the conductive wire portion of the electric wire of the load is exposed. It is possible to perform the wiring connection work.

In addition, the earth leakage safety device according to a third aspect of the present invention provides an auxiliary power output connected to one or both of the main power output terminal and the auxiliary power output terminal in parallel with these power output terminals. A terminal is provided. And these spare power output terminals are preferably configured in the form of an outlet which can be engaged with a plug provided on a wire of a load connected to these terminals, as described in claim 4. It is characterized by being.

That is, in the invention according to claim 3,
Since at least one of the main power output terminal and the auxiliary power output terminal is provided with a spare power output terminal connected in parallel with these power output terminals,
For example, by providing a spare power output terminal on the main power output terminal side, it is possible to detect leakage of a plurality of devices by the leakage detection circuit in the leakage protection device, while the auxiliary power output terminal is provided on the auxiliary power output terminal side. By providing the terminals, it is possible to stably supply power to a plurality of devices even after the power supply on the main power output terminal side is cut off. When these power supply output terminals are configured in the form of outlets, when additional equipment is connected to each power supply terminal, additional connection can be easily made by inserting a plug provided in each equipment.

Further, the hot water supply device according to the fifth aspect of the present invention includes at least an electrically driven freezing prevention heater, and a first aspect.
A hot water supply device provided with the earth leakage safety device according to any one of claims 4 to 7, wherein a power supply circuit of the water heating device including the freeze prevention heater is connected to a main power output terminal of the earth leakage safety device. The auxiliary power output terminal is connected in parallel to an electric circuit connecting the main power output terminal and the freeze prevention heater via a transformer.

That is, in the hot water supply apparatus according to the fifth aspect, the power supply circuit of the freeze prevention heater is connected to the auxiliary power supply output terminal of the electric leakage safety device, and the relay operates without detecting the electric leakage. In a state where the heater is not supplied, the power is supplied to the freeze prevention heater through the main power output terminal, and when the leakage is detected and the relay operates, the freeze prevention heater is supplied to the freeze prevention heater through the auxiliary power output terminal. It supplies power. When power is supplied via the auxiliary power output terminal, the auxiliary power output terminal and the freeze prevention heater are insulated by a transformer interposed between the auxiliary power output terminal and the freeze prevention heater. Even if insulation failure such as wire stubs occurs in the electric path of the freeze prevention heater, there is no leakage path from the auxiliary power output terminal,
There is no leakage.

In the water heater according to a sixth aspect of the present invention, there is provided a normally open relay for detecting a decrease in outside air temperature and short-circuiting the electric circuit in an electric circuit connecting the auxiliary power output terminal and the freeze prevention heater. It is characterized in that electric means is provided.

That is, the invention according to claim 6 is preferably applied to a water heater in which the on / off control of the freeze prevention heater is controlled by a controller of the water heater. Between the power output terminal and the freeze prevention heater, there is provided a relay means which operates independently of the control unit. In other words, according to the invention of claim 6, even when the leakage detection circuit detects the leakage and the power supply to the control unit is cut off, the relay detects the decrease in the outside air temperature and freezes. The preventive heater can be turned on.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an earth leakage safety device and a hot water supply device according to the present invention will be described in detail with reference to FIGS.

FIG. 1 is a circuit diagram showing a basic circuit configuration of an earth leakage safety device according to the present invention.
An earth leakage breaker individually connected to or incorporated in various electric devices, comprising a power input terminal 2, a main power output terminal 3,
It comprises a leakage detection circuit 4, a relay 5, and an auxiliary power output terminal 6 as main parts.

The power input terminal 2 is a power input terminal connected to various power sources E such as a commercial power source. The power input terminal 2 is connected via a relay 5 and a leakage detection circuit 4 as shown in FIG. Connected to the power output terminal 3. The power input terminal 2 is formed of a so-called screw-type bracket.

More specifically, as shown in the external configuration diagram of FIG. 2, a base metal 21 serving as a base for fixing an electric wire (not shown) wired from a commercial power supply, A holding bracket 22 for holding down the electric wire;
Tightening screw 2 for tightening and fixing this holding member 22
And 3. When connecting the electric wires, the conductor at the tip of the electric wire is exposed, and the tightening screw 23 is tightened while the conductor is inserted between the base metal fitting 21 and the holding metal fitting 22. As a result, the conducting wire portion of the electric wire is sandwiched and fixed between the base metal fitting 21 and the holding metal fitting 22, and the electric wire and the power input terminal 2 are electrically connected.

The main power supply output terminal 3 is a power supply output terminal connected to a power supply circuit (load Z) of various electric devices. It is composed of metal fittings (see FIG. 2).

The main power output terminal 3 is connected to FIG.
As shown in FIG.
By connecting a power supply circuit of another electric device (not shown) to the spare power supply output terminal 7, it is possible to detect leakage of the other electric device and shut off power supply at the time of leakage. It has been. As a form of the spare power supply output terminal 7, the above-mentioned screw type may be adopted, but as shown in FIG.
It is preferable to adopt the form of an outlet.

That is, since the other electric equipment connected to the spare power output terminal 7 is an electric equipment which does not have its own leakage safety device, the form of the spare power output terminal 7 is as follows. It is preferable to use a plug that can be engaged with a plug provided at the end of the electric wire of the electric device so that the plug can be easily connected. Note that the specific form of the outlet used here is appropriately selected according to the type of power supplied to the power input terminal 2 and the like.

The earth leakage detecting circuit 4 is a conventionally known earth leakage detecting circuit. For example, by detecting a ground fault current from a difference between a forward current and a return current of a current flowing from the main power output terminal 3 to a load, It detects a leakage of an electric device connected to the main power output terminal 3 (or the spare power output terminal 7).

The relay 5 has two contacts (a) as shown in FIG.
(A contact and a b-contact), and is configured such that when a leakage is detected in the leakage detection circuit 4, the contact is switched from the a-contact to the b-contact.
That is, the main power supply output terminal 3 (or the standby power supply output terminal 7) is connected to the a contact side of the relay 5 and the main power supply output terminal 3 (or the standby power supply terminal 3) is connected via the a contact in a normal state. Power is supplied to the power supply circuit of the electric device connected to the power supply output terminal 7), and the contact is switched (a contact is opened) when a leakage is detected, so that the power supply to these electric devices is cut off. ing.

The auxiliary power supply output terminal 6 is a power supply output terminal for outputting power when a leakage is detected in the leakage detection circuit 4. The auxiliary power supply output terminal 6 is connected to the contact b of the relay 5 described above. Have been. Therefore, when the electric leakage is detected by the electric leakage detection circuit 4 and the contact of the relay 5 is switched to the contact b, the power input to the power input terminal 2 is output from the auxiliary power output terminal 6.

Therefore, the auxiliary power supply output terminal 6
A power supply circuit of an electric device that requires a constant power supply is connected. Specifically, by connecting the main power supply output terminal 3 and the auxiliary power supply output terminal 6 in parallel to the power supply circuit of the electric device, even when the power supply from the main power supply output terminal 3 is cut off, The wiring is connected so that power can be supplied from the auxiliary power output terminal 6.

As a specific form of the auxiliary power supply output terminal 6, a screw-type metal fitting is preferably employed similarly to the power supply input terminal 2 (see FIG. 2). The auxiliary power supply output terminal 6 is provided with a spare power supply output terminal 8 in the form of an outlet in parallel with the terminal 6 as in the case of the main power supply output terminal 3 described above.

Reference numeral 10 shown in FIG. 2 denotes a display lamp which emits light when an electric leakage is detected in the electric leakage detection circuit 4, and reference numeral 11 denotes a test lamp for generating a pseudo electric leakage state in the electric leakage safety device 1. Reference numeral 12 denotes a reset switch, and reference numeral 13 denotes a ground lead. Since the details are not directly related to the configuration of the present invention, the description is omitted here, but the configuration is the same as that of the conventional earth leakage safety device. Reference numeral 14 denotes a mounting flange for mounting the electrical leakage safety device 1 to a wall surface or a housing of an electric device.

FIG. 3 shows an example in which the earth leakage safety device 1 thus configured is applied to a hot water supply device. Specifically, FIG. 3 shows a case where the earth leakage safety device 1 according to the present invention is connected to a power supply circuit of a freeze prevention heater Z 'of a hot water supply device (not shown).

That is, in FIG. 3, while the commercial power supply (AC 100 V) is connected to the power input terminal 2 of the earth leakage safety device 1, the main power output terminal 3 is connected to the freeze prevention heater Z 'by an electric wire. (Electric circuit) 15. The anti-freezing heater Z 'is provided with a relay 16 for the anti-freezing heater, which is controlled to be turned on and off by a control unit of the hot water supply device (not shown), on the electric wire 15, and is provided around the water supply pipe or the like. When the temperature of the piping portion is lowered and freezing in the piping is expected, the control unit of the hot water supply device short-circuits the relay 16 to turn on the freeze prevention heater Z '.

On the other hand, the auxiliary power output terminal 6 is connected in parallel to an electric circuit connecting the main power output terminal 3 and the freeze prevention heater Z 'via a transformer 17. Specifically, the auxiliary power supply output terminal 6 is connected to the primary winding 17a of the transformer 17, and the secondary winding 17b of the transformer 17 is connected to both ends of the freeze prevention heater Z '. 15 (indicated by reference numeral c in the figure). At this time, the connection point c is located closer to the freeze prevention heater Z ′ than the freeze prevention heater relay 16,
As a result, the closed circuit formed by the secondary winding 17b of the transformer 17 and the freeze prevention heater Z 'is configured independently of the operation of the freeze prevention heater relay 16, in other words, the control unit. You.

On the other hand, the closed circuit is provided with a normally open relay means 18 for detecting a drop in the outside air temperature and short-circuiting the electric circuit. As the relay means 18, a device that does not require electricity as a driving source, such as a thermostat, is suitably used. That is, the closed circuit including the transformer 17 is supplied with power when the power supply to the circuit connected to the main power supply output terminal 3 is cut off. This is because, if a driving power supply is required for the relay 18 itself, a separate power supply circuit is required for the relay means 18.

In the hot water supply apparatus configured as described above, if leakage occurs in the power supply circuit of the hot water supply apparatus connected to the main power supply output terminal 3, the freeze prevention heater Z will be described as follows. 'Is continued to be supplied.

That is, when a leakage occurs in the power supply circuit of the water heater, the leakage detection circuit 4 detects the leakage,
While the power supply to the main power output terminal 3 is cut off, the contact of the relay 5 is switched from the a-contact to the b-contact as in the description of the earth leakage safety device 1.

When the contact of the relay 5 is switched to the contact b, power is taken out from the auxiliary power supply output terminal 6. At this time, between the freeze prevention heater Z 'and the auxiliary power supply output terminal 6 Since the thermostat 18 is interposed, the anti-freezing heater Z 'is not energized at this time, and the anti-freezing heater Z' remains off.

Then, the temperature of the outside air, etc.
When the operating temperature of the thermostat 18 decreases, the contact of the thermostat 18 is changed from the open state to the short-circuit state, and the power supplied to the auxiliary power output terminal 6 is applied to the anti-freezing heater Z 'via the transformer 17, and the anti-freezing heater Z 'is turned on. That is, in the example shown in FIG.
The operation of the thermostat 18 controls the power supply to the freeze prevention heater Z 'even when the power supply from the main power supply output terminal 3 is cut off and the power supply to the control unit of the hot water supply device (not shown) is stopped. Have been.

In addition, in this case, even if insulation failure such as wire breakage occurs in the freeze prevention heater Z ', the power supplied to the freeze prevention heater Z' is insulated by the transformer 17 so that the leakage path is It is not formed, and the current from the auxiliary power output terminal 6 does not become a ground fault current.

The above-described embodiment is merely a preferred embodiment of the present invention, and the present invention is not limited to this, and various design changes can be made within the scope.

For example, in the above-described embodiment, a configuration is shown in which both the main power supply output terminal 3 and the auxiliary power supply output terminal 6 are provided with one spare power supply output terminal 7 and 8, respectively. The power supply output terminal may be provided on only one of the output terminals or a plurality of power output terminals may be provided on each output terminal according to the environment in which the earth leakage safety device 1 is used.

In the above embodiment, the case where the power input terminal 2, the main power output terminal 3, and the auxiliary power output terminal 6 are of a screw type has been described, but the form of each terminal is not limited to this. The design can be changed as appropriate. Similarly, the design of the spare power supply output terminals 7 and 8 can be appropriately changed.

Further, in the above-described embodiment, the form in which the load such as the freeze prevention heater Z 'is connected to the auxiliary power supply output terminal 6 to operate this load has been described. May be configured to be used as an input of an alarm device outside the device so that the alarm device notifies of the electric leakage.

[0048]

As described in detail above, claim 1 of the present invention
The earth leakage safety device according to claim 1, wherein at least a power supply input terminal connected to a power supply, a main power supply output terminal connected to a load, and an electric leakage that detects a leakage of an electric circuit on a load side connected to the main power supply output terminal In a ground fault safety device comprising a detection circuit and a relay that operates when a ground fault is detected in the ground fault detection circuit, the relay is configured as a two-contact type relay, and a contact side connected when a ground fault is detected. Since the auxiliary power output terminal is provided, even when the power supply to the main power output terminal side is interrupted when the leakage is detected, power can be taken out from the auxiliary power output terminal.

Therefore, for example, when the earth leakage safety device is attached to a device having a circuit which always requires power supply, even if the earth leakage safety device is activated and the power supply from the main power output terminal is cut off, this auxiliary power Since power can be extracted from the output terminal, power can be continuously supplied to the circuit.

Further, in the earth leakage safety device according to the third aspect of the present invention, a spare power supply output connected in parallel with the power supply output terminal to one or both of the main power supply output terminal and the auxiliary power supply output terminal. Since the terminals are provided, by using these spare power output terminals, it is possible to detect leakage of a plurality of devices and supply power when leakage is detected. Moreover, by configuring these spare power output terminals in the form of outlets,
Connection between these terminals and the power supply circuit of the device is facilitated, and a versatile earth leakage safety device can be provided.

A hot water supply apparatus according to a fifth aspect of the present invention is a hot water supply apparatus having at least an electric freeze prevention heater and an electric leakage safety device according to the present invention. Each of the power supply circuits of the hot water supply device including the freeze prevention heater is connected, and the auxiliary power output terminal is connected in parallel to an electric circuit connecting the main power output terminal and the freeze prevention heater via a transformer. Therefore, even when a short circuit occurs in the power supply system of the hot water supply device, power is supplied to the freeze prevention heater via the auxiliary power supply output terminal. As a result, the disadvantage that the freeze prevention heater does not operate due to the operation of the earth leakage safety device is solved. In addition, in this case, the leakage detection of the freeze prevention heater itself is performed at the main power output terminal side, and the power supplied from the auxiliary power output terminal passes through the transformer, so that a leakage path is not formed, so that the equipment is not used. It is also preferable for safety measures.

Further, in the hot water supply apparatus according to the sixth aspect of the present invention, a normally open type relay for detecting a decrease in outside air temperature and short-circuiting the electric circuit is provided in the electric circuit connecting the auxiliary power output terminal and the freeze prevention heater. Since the power supply means is provided, even when the power supply on the main power supply output terminal side is cut off, the on / off control of the freeze prevention heater can be performed by the power relay means.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a basic circuit configuration of an earth leakage safety device according to the present invention.

FIG. 2 is a plan view showing an example of the appearance of the earth leakage safety device.

FIG. 3 is a circuit diagram showing an example of a circuit configuration when the earth leakage safety device is connected to a freeze prevention heater of a water heater.

FIG. 4 is a circuit diagram showing a basic circuit configuration of a conventional earth leakage safety device.

FIG. 5 is a circuit diagram showing an example of a circuit configuration when a conventional earth leakage safety device is connected to a freeze prevention heater of a water heater.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electric leakage safety device 2 Power input terminal 3 Main power output terminal 4 Electric leakage detection circuit 5 Relay 6 Auxiliary power output terminal 7,8 Spare power output terminal 10 Indicator lamp 11 Test switch 12 Reset switch 16 Freeze prevention heater relay 17 Transformer 18 thermostat (relay means) E power supply Z load Z 'freezing prevention heater (load) a, b Relay contacts

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) H02H 3/16 H02H 3/16 B (72) Inventor Kazuo Watari 93 Edocho, Chuo-ku, Kobe-shi, Hyogo Co., Ltd. Within Noritz (72) Inventor Masanori Yamashita 93, Edo-cho, Chuo-ku, Kobe, Hyogo Prefecture Inside Noritz (72) Inventor Yutaka Nakamura 93, Edo-cho, Chuo-ku, Kobe, Hyogo Prefecture F-term (reference) 5G004 AA01 AB02 BA01 5G030 EA00 XX18 YY13

Claims (6)

[Claims] 1. A power supply input terminal connected to a power supply, a main power supply output terminal connected to a load, and an electric leakage detection circuit for detecting electric leakage in an electric circuit on a load side connected to the main power supply output terminal. And a relay that operates when a leakage is detected in the leakage detection circuit, wherein the relay is configured as a two-contact type relay, and an auxiliary contact is provided on a contact side connected when a leakage is detected. An earth leakage safety device having a power output terminal. 2. An auxiliary power supply output terminal according to claim 1, wherein said auxiliary power supply output terminal is formed in a form of a metal fitting which enables an electric wire of a load connected to said terminal to be electrically connected by screwing. Earth leakage safety device. 3. A spare power supply output terminal connected in parallel with the power supply output terminal is provided at one or both of the main power supply output terminal and the auxiliary power supply output terminal. Item 7. The earth leakage safety device according to Item 1. 4. The power supply output terminal according to claim 3, wherein the spare power supply output terminal is configured in the form of an outlet that can be engaged with a plug provided on an electric wire of a load connected to the terminal. Earth leakage safety device. 5. A hot water supply device comprising at least an electrically driven freezing prevention heater and an electric leakage safety device according to claim 1, wherein a main power output of the electric leakage safety device is provided. Each of the power supply circuits of the water heater including the freeze prevention heater is connected to the terminal, and the auxiliary power output terminal is connected in parallel with an electric circuit connecting the main power output terminal and the freeze prevention heater via a transformer. A hot water supply device being connected. 6. A normally open type relay means for detecting a decrease in outside air temperature and short-circuiting the electric circuit is provided in an electric circuit connecting the auxiliary power output terminal and the freeze prevention heater. The hot water supply apparatus according to claim 5, wherein