mbrooke
Batteries Included
- Location
- United States
- Occupation
- Technician
Perhaps but which one would you expect to do better in those conditions?
Copper, you have a point
Romex and SER ampacities.
- Thread starter Thomas R
- Start date
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Copper, you have a point
trojans4
Member
- Location
- Iowa
- Occupation
- Semi -retired master electrician. Fully retired math and physics teacher.
Someone I know called me about the size of wire needed for a new hot tub. It is a 6 person hot tub. I have not seen the tub or specs but the owner is looking for the info. The only thing he remembered was that somewhere it said it would draw 40A and need a 50A GFCI breaker. Does that make sense? If it draws 40A you could use #8 wire but would you use a 50A breaker? His question was probably in response to the huge increase in copper wire prices as I then looked and saw the price of 50' of 6/3 was $256 and the price of 8/3 was $169.
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- Location
- New Jersey
- Occupation
- Journeyman Electrician
If it's NM cable you need #6 for a 50 amp OCPD.
kwired
Electron manager
- Location
- NE Nebraska
- Occupation
- EC
I agree with you . If 100% of non continuous load plus 125% of continuous load is 55 or less you can use #6 copper @ 60C ampacity on a 60 amp breaker.
kwired
Electron manager
- Location
- NE Nebraska
- Occupation
- EC
Possible in that case 8-3 was older stock that hadn't had price increased yet? I'd expect them to be closer to one another than that. And if a 50 foot package at big box store they were pricey anyway even before copper went up. I could get a 50 foot cut piece at my electrical supply house for less than those prepackaged 50 foot pieces at a big box store. (this one doesn't cut anything smaller than 8 AWG so you buying at least 250 feet of 10 AWG NM cable or go to big box and pay higher price per foot if you don't want the leftover amount.
- Location
- Illinois
- Occupation
- retired electrician
Article 338 does not have language like is found in 334.80 and is not limited to the 60°C ampacities.
Even where you use SE as interior feeder and branch circuit wiring, you are not limited to the 60°C ampacity. Where SE is used for interior feeder or branch circuits, the installation shall comply with the requirements of Part II of Article 334, excluding 334.80.
Rick 0920
Senior Member
- Location
- Jacksonville, FL
- Occupation
- Electrical Instructor
I have used 6/3 w/ground NM-B on hut tub installations before and protected it with a 2 pole 60 amp breaker. Unless I am missing something, Art. 240.4 (B) would allow this. #6 at 60 degrees C. has an ampacity of 55 amps, which is not a standard breaker size. Using the next standard size is permissible if (1), (2), and (3) are met.
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
That is true but sometime it is hard to find a 60 amp gfci. 50 amp gfci are much more available around here.
Now, have you ever read the instructions to the tub. Some state that the equipment grounding conductor must be full sized. You can't do that with nm cable that is why we always tried to pipe it.
Rick 0920
Senior Member
- Location
- Jacksonville, FL
- Occupation
- Electrical Instructor
I have not seen requirements for a full size ground on the few that I have done. That's not to say that both myself and the inspector have missed that. I have seen that all of the hot tubs' factory installed wiring bonds all metal non current-carrying parts with a #8 solid cu. conductor. Thanks for the input. I will check more closely on any future installations.
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
It has been awhile since I have seen them. Hopefully they got smart and changed their evil ways
mbrooke
Batteries Included
- Location
- United States
- Occupation
- Technician
Good reason for a full size ground when dealing with low body resistance IMO.
For Massachusetts there is an amendment that only requires 60 degree column when installed in thermal insulation
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