I wired a storage room and run one 20 amp circuit for some outlets and to power the water heater and furnace does this circuit have to be gfci protected?? Or can I install regular receptacles


If this area is an unfinished area of a basement or crawl space then GFI protection is definitely required for ALL 120V, 15A & 20A receptacles. No exceptions, other than for fire or burglar alarm systems.

The furnace must be dedicated and should NOT have a cord and plug.

2011/14 NEC

422.12 Central Heating Equipment

Central heating equipment other than fixed electric space-heating equipment shall be supplied by an individual branch circuit.

Exception No. 1: Auxiliary equipment, such as a pump, valve, humidifier, or electrostatic air cleaner directly associated with the heating equipment, shall be permitted to be connected to the same branch circuit.

Exception No. 2: Permanently connected air-conditioning equipment shall be permitted to be connected to the same branch circuit.

If the water heater has a typical 120V cord and plug you have no choice but to use GFI protection.


I started this as a comment on Speedy Petey's answer and ran out of room. He's completely correct.

I was just going to comment that GFCI protection can be implemented with GFCI circuit breakers in the panel, in which case you would install regular receptacles, and protection extends to everything downstream from the GFCI device on the same circuit. The same applies if you install a GFCI receptacle and connect additional regular receptacles to the load side of the GFCI. You only need one GFCI for the whole circuit.

So you need to run at least two circuits and maybe three. One of them will be hard-wired into the furnace. The other(s) will feed the receptacles and you might want a dedicated (or mostly dedicated) circuit for the water heater, depending on how much electricity it uses.

For example, this point-of-use 120V water heater draws 1,500 Watts. That's 12.5A on a 120V circuit. That is below the 80% continuous load limit on a 20A circuit (it's above 80% on a 15A circuit), but there isn't a ton of headroom and it's jut one device. Plug something like a space heater or hair dryer into the same circuit when the water heater is on, and you will trip the circuit breaker.

  • 1
    I think the rule with water heating equipment, is that it can be on a shared circuit if it uses less than 50% of the capacity of the circuit. But as always, I could be mistaken.
    – Tester101
    Jul 20 '15 at 2:09

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