Neutral sizing for hot tub

[kwired]

K wired, I agree with you however 110.3(B) will most likely be the deciding factor here. Knowing the manufacturer and model of hot tub would help significantly in answering the original posters question. As I wrote before there is a decent chance that this hot tub does not even require a neutral. If it does number 8 would be more than sufficient the neutral would never see more than 40 amps, it's unlikely that , even if needed, it would see 15 amps. Article 680 installs are nothing to Monkey around with however I do not see a problem here with running a number eight neutral to the hot tub

I understand and yes it seems many tubs do state minimum conductor size - even larger then what seems necessary on ungrounded and EGC in some instances. Seen many hot tubs that require 6 AWG on all conductors yet don't really give you space to install them very easily

Also agree 680 installs aren't something to monkey around with but still don't see how running a 14 AWG neutral makes any significant increased hazard to the user if it isn't loaded to more then it's ampacity. GFCI and bonding are the main things that make differences here.

 

[Dennis Alwon]

It is different than the rule for the feeder for 2 reasons. The first is that the feeder rule is not to be found for branch circuits and secondly, the neutral is required to be no smaller than the equipment grounding conductor. What you are saying is that it can be smaller than the equipment grounding conductor. You have to be careful for neutral to hot short circuit.

I guess will have to agree to disagree. If the intent was to be the same as a feeder than they would have used the same wording.

 

[kwired]

It is different than the rule for the feeder for 2 reasons. The first is that the feeder rule is not to be found for branch circuits and secondly, the neutral is required to be no smaller than the equipment grounding conductor. What you are saying is that it can be smaller than the equipment grounding conductor. You have to be careful for neutral to hot short circuit.

I guess will have to agree to disagree. If the intent was to be the same as a feeder than they would have used the same wording.

This discussion has come up before but for other situations. IMO neutral to hot short circuit shouldn't be a concern. If it were we wouldn't be able to run multiple circuits of different ratings in a raceway unless they were all sized per the highest setting overcurrent device involved.

If you pulled a 20 and 50 amp circuit through same raceway would you run a 12 AWG neutral for the 20 amp circuit even though there is a chance it may fault to one of the 50 amp ungrounded conductors?

I don't know why NEC has minimum grounded conductor for feeders set at same as EGC, but it doesn't have same language as it relates to branch circuits.

I run into a lot of equipment that only has a 120 volt load that is a motor control contactor coil - and can easily be a motor operated equipment that needs 50, 60, even 100 amp overcurrent device on the motor circuit. I always run 14 AWG neutral to these with the branch circuit. Makes more sense if the equipment suppliers would just use a 240 volt coil in those applications though, but from what I have seen they likely are buying larger quantities of contactors - all 120 volt to simplify things for them - should the equipment it gets used in be 480 volts input then they add a control transformer, but for 208 or 240 volt applications they just tap the supply conductor for control and make install provide a neutral with the supply.

 

[GoldDigger]

But if the neutral is not actually used at the equipment, the only chance for a hot short will necessarily be to the EGC and not the neutral.

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