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I'm re-wiring my kitchen and I'm taking notes on the load of all the appliances and lighting, etc. I noticed the following about my refrigerator:

From Frigidaire Professional 19 cu ft All Refrigerator

It states a 20A circuit requirement, but why? The stated load doesn't come anywhere close to the allowed load even on a 10A circuit, let alone a 15A circuit. Can refrigerators have really big spikes in load or something? And if so, wouldn't one want the breaker to trip?

  • I would think that unless it comes with a 20A plug (one of the prongs is rotated 90 degrees), it should be fine on a 15A circuit that's not shared with anything else. – Johnny Dec 14 '14 at 6:13
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    I agree with Johnny. The silly 20A requirement is an unjustified CYA move by the legal department. – Speedy Petey Dec 14 '14 at 13:17
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Motors often have a surge load at startup which is much higher than their running load. If they've gone to the trouble of specifying this, I highly recommend taking their word for it.

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    ...and motors attached to compressors, doubly so. – Ecnerwal Dec 14 '14 at 5:56
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    With motors, startup load inrush current is always much more than run current. It has to do with motor back-emf, a non-turning motor has only the winding resistance and inductance limiting the current, as it spins up to running speed the stator induces a reverse voltage in the windings that lowers the current. – Fiasco Labs Dec 14 '14 at 7:42
  • There is still NO WAY the startup current is even close to that high. Even so, the circuit breaker is designed to handle it. – Speedy Petey Dec 14 '14 at 13:14
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    @SpeedyPetey There is also the case for stall current. In the case that there is a brown out which causes the motor to stall it will be unable to start up until the pressure has equalized. When the motor is stalled it will take even more current than during start-up, and will continue to do so until the thermal protection device disconnects the power to the motor. You definitely want that to trip well before the trip point of the breaker. – Brad Gilbert Dec 14 '14 at 21:26
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    All that is wonderful, and not anything new to me, but I stand by my assertion that requiring a 20A circuit for a 5A refer is silly. – Speedy Petey Dec 14 '14 at 23:01
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You do not want a stalled motor to "hang in there" during brownout etc. Size it to about 15 will add protection; not detract. 20 Amp might well be the poorer choice.

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    This fails to take into account that hermetic motor-compressors, by and large, have internal thermal protectors that will trip the motor out if it "hangs" as you describe – ThreePhaseEel Jun 13 at 2:27

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