Instantaneous-Type Water Heater

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llrodriguez

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Can anyone tell me if an instantaneous-type water heater (those used right under the sink) must have a disconnect mounted under with it under the sink. I've looked thru NEC Art. 422 but I'm still unclear. The unit is a 120v, 3kW, and rated for 25 amps. It would seem kind of strange to have a disconnect next to this little box under a sink and manufacture's installation instructions don't show one. Thanks for your help.
 
Re: Instantaneous-Type Water Heater

422.31 Disconnection of Permanently Connected Appliances.
(A) Rated at Not Over 300 Volt-Amperes or 1/8 Horsepower. For permanently connected appliances rated at not over 300 volt-amperes or 1 /8 hp, the branch-circuit overcurrent device shall be permitted to serve as the disconnecting means.
(B) Appliances Rated Over 300 Volt-Amperes or 1/8 Horsepower. For permanently connected appliances rated over 300 volt-amperes or 1/8 hp, the branch-circuit switch or circuit breaker shall be permitted to serve as the disconnecting means where the switch or circuit breaker is within sight from the appliance or is capable of being locked in the open position.
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Re: Instantaneous-Type Water Heater

Linda:

Ryan has correctly pointed out 422.31. We usually add a means of disconnecting each appliance for safety when making repairs unless the customer has a lock and tag procedure for their facility. Better to be safe than sorry.
 
Re: Instantaneous-Type Water Heater

You can use the proper rated snap switch in a device box under the sink, or the easier way is to install a lock out device on the circuit breaker for the water heater. These are inexpensive metal adapters that are installed on and stay on the circuit breaker, check the mfgs catalog for the panelboard you have.
 
Re: Instantaneous-Type Water Heater

Yes Ryan has it right.Why would you treat it differant than a 40 gal water heater ? Now while i do not think of this as safe it is the cheapist way out .And the same rules apply to to instant whole house units at 24 kw. Good NO but if price is object and usually is then that is what they get.Sorry but people tend to open wallets for only things they can see or use and not for safety of the repair man.I was forced to install a instant hot on a house with outside panel.Yes legal.
 
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