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questioning what an electrical inspector told me and hoping for a bit more detail.

Back story: I installed a hot tub in my backyard (NYC, NY) and hired an electrician to run a 208V circuit out to it. I asked the electrician to run 6AWG cable in rigid conduit. The heater + pump only pull ~32A, but I wanted some wiggle room in case I want to add extra lights, audio system, etc to the hot tub. Since 6AWG can support up to 55A, I've got a 50A GFCI breaker guarding this circuit.

Inspector comes, and says we need to swap the breaker to a 35A breaker because he needs to "match the breaker size to the appliance current". The inspector says this is a code requirement. Is this true? Seems incorrect (but what do I know). I'm pretty sure the breakers protect the wire from frying (not the appliances). I fact, I could install a circuit and have nothing plugged into the recepticals...how is that not in violation of "matching the breaker size to the appliance current"? Maybe the difference is that the hot tub is hard wired in (not plugged into a receptical)?

Anyways, I cannot contact the inspector again since he told me he will not answer any follow up emails. I called the electrician who did the work and the electrician told me, yes, it is a code requirement, but told me he does not have the patience to tell me which code it is and hung up on me (great).

Can anyone shed some light here?

natsuki_2002
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    What do the instructions/ manual for the hot tub call for as far as breaker size? – JACK May 27 '21 at 16:30
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    Not clear from question how/where you'll patch in more gadgets. If the new cable serves the tub directly, you'll have to do some new electrical work regardless, so why worry now? Just install the 35A breaker. And then, when you do get around to it .... lights and sound should add one Amp, MAYBE. You'll still be ok with a 35A breaker. And you'll still have your 50A one sitting around if you want to put it back. – jay613 May 27 '21 at 16:33
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    Because OP just spent $100 on the 50A breaker... – Harper - Reinstate Monica May 27 '21 at 16:40
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    Does the tub provide a maximum overcurrent value on the name plate? Motors require 125% of the demand. is there an air pump also? To be able to add additional circuits you would need a sub panel having the larger breaker feed the sub then the tub breaker @35-40 and you could add the additional circuits. If the tub manufacturer states the maximum overcurrent is 50 show that to your inspector, if the MFG states 35 the inspector is correct but in any case to be able to add circuits you will need a sub panel as a 120v 15 or 20 amp receptacle can not be fed with larger than a 20a breaker. – Ed Beal May 27 '21 at 16:41
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    If the circuitry and wires inside the hot tub are only designed to handle a max current of 40 amps then having a 50 amp breaker will protect your lines leading up to the tub just fine but the tub itself is now a fire hazard because it could malfunction and won't trip the breaker until it's 25% over its rated maximum. I recently had an A/C unit installed which specified a max breaker size of 25 amps. – MonkeyZeus May 27 '21 at 17:43
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    Can you post make/model and nameplate information for your hot tub please? Also, did they run a *cable* in conduit?! – ThreePhaseEel May 27 '21 at 23:19
  • **M**aximum **O**vercurrent **P**rotection. "MOP : 35A" ? – Mazura May 28 '21 at 04:19
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    A 50A fault will murder your pump. So it needs a smaller breaker - one that will actually protect it. Breakers protect wires, typically, but for large equipment they also protect the equipment and need to be sized appropriately. Too big is no good. You need a subpanel for multiple loads. – J... May 28 '21 at 17:39

2 Answers2

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The usual setup is:

  • Large breaker, matched to wire size, in the main panel.
  • Wires (protected by breaker) to a subpanel
  • In the subpanel, a separate breaker & wires matched to each appliance.

GFCI is both code and critical life safety for hot tubs. The wonderful thing about GFCI protection is that it can be at almost any level - breaker in the main panel, breakers in subpanel, combined with receptacles. You generally don't want to (if available in that size) use a GFCI as your actual main breaker, because then power to your whole house would go out when there is a ground fault, as well as some other possible problems. And in the case of a hot tub, you don't want to put the GFCI any farther than the subpanel for a bunch of reasons. Since you already have a 50A GFCI breaker, you can go ahead and use that for the feed to the subpanel and you don't need any GFCI breakers (with their sensitive electronics) out in the subpanel.

32A for one appliance would normally get a 40A breaker. If that is really two loads - e.g., heater 24A, pump 8A (making up those numbers) then you would have 2 breakers - 30A for the heater, 15A or 20A (since that is normal for most small loads in the US) for the pump. You would also have either a shutoff switch or, often easier/cheaper, a main breaker in the subpanel which could be any size (since the individual appliances are protected by individual breakers and the subpanel and its wiring are protected by the breaker back in the main panel). The subpanel can have additional circuits - e.g., a separate lighting circuit, a convenience receptacle, etc.

manassehkatz-Moving 2 Codidact
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    Great answer! + A small sub-panel would facilitate additional circuits. I'm amused by the attitude New Yorker's (and NJ) have to each other, so nasty. Here in the great PNW we're much more congenial. – George Anderson May 27 '21 at 16:43
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    Yes, and since the existing GFCI breaker will provide all the GFCI protection needed, a plain panel will suffice. This is the way to go. – Harper - Reinstate Monica May 27 '21 at 20:02
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NEC 110.3(B) obey labeling and instructions.

That's it. That's the NEC code that they won't tell you. It's the third paragraph in the entire NEC.

So if the hot tub complied with NEC 110.2 (use approved equipment), it will have come with instructions and/or labeling. Those will state the breaker size(s) you must use for it.

Don't harsh on the electrician for doing literally exactly what you said to do. The fact that you chose to do that was sort of a mistake, but it was not the electrician's mistake!

It sucks to have to replace a $100 breaker, but I think you don't have to.

It's time for a subpanel.

The way out of this without wasting that breaker is to fit a subpanel here. You don't need a "hot tub subpanel" since those are defined by having a GFCI breaker, and you already have one. The GFCI breaker already in your main panel will protect the subpanel and everything wired into it, and everything plugged into that.

A plain subpanel populated with plain breakers, near the hot tub (there's a correct distance) is exactly what you need, and that stuff is cheap.

You might even call the guy back and say "I learned my lesson, hook me up with a subpanel".

I'm a fan of BIG BIG subpanels. Particularly, note that your feeder is good for 55A (or 65A if the preferred wire for conduit was used). And in this context you round up to the next available breaker size; so this subpanel could be fed by as large as a 70A breaker. That supports a lot more stuff than you'd think, especially if it's 3-phase! Spaces are cheap, and I myself would install a 24 or 30 space panel. I admit that's a little extreme.

You must hook up neutral and ground correctly. The feeder must have separate neutral and ground, but I'm sure it does if a pro installed it in 2021.

Note that any ground fault on any circuit in this subpanel will trip the GFCI breaker back in the main panel. Ground faults are real problems; when they show up, just fix them.

Harper - Reinstate Monica
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