105? Wire Terminations

[little george]

I inspected a Kohler steam unit for a sauna and the directions on the cover for the J-box says 105? wire terminations. Not enough detail for me to go on so I asked the contractor to use 105? wire for the final connection on the unit. Has anyone run into this before? The installation manual is silent on this and the nameplate says use #6 copper wire and install on a 70a. circuit breaker. I don't see a problem with the circuit since it is a heating unit but I guess the contractor is having trouble finding 105? #6 copper wire.

 

[NolaTigaBait]

I inspected a Kohler steam unit for a sauna and the directions on the cover for the J-box says 105? wire terminations. Not enough detail for me to go on so I asked the contractor to use 105? wire for the final connection on the unit. Has anyone run into this before? The installation manual is silent on this and the nameplate says use #6 copper wire and install on a 70a. circuit breaker. I don't see a problem with the circuit since it is a heating unit but I guess the contractor is having trouble finding 105? #6 copper wire.

i looke at this today...the #12 thhn i bought says on the spool its good for 105 when used for what you described

 

[Twoskinsoneman]

I inspected a Kohler steam unit for a sauna and the directions on the cover for the J-box says 105? wire terminations. Not enough detail for me to go on so I asked the contractor to use 105? wire for the final connection on the unit. Has anyone run into this before? The installation manual is silent on this and the nameplate says use #6 copper wire and install on a 70a. circuit breaker. I don't see a problem with the circuit since it is a heating unit but I guess the contractor is having trouble finding 105? #6 copper wire.

Just throw out my opinion but I don't believe just because the terminal is rated at a higher rating than you wire you are in violation.

On another KINDA related note I once ask a Cummins dealer how he could get away with using undersized wires inside a genset (between generator and gen-mounted OCPD) he told me they used 105 wire and were able to much smaller wires due to the ampacity.

 

[NolaTigaBait]

used for what you described

for the internal wiring of an appliance

 

[KevinVost]

I had the same problem with Lucifer down lights that required 105 degree wiring within 12" of the ballast, the MC they were using was rated 90. The contractor was researching 105 degree MC or single conductors, however in the manufactures specs they allowed 90 degree wire if a low wattage lamp was installed, so thats what they did. Then they made the owner sign and agree to only use the lower wattage bulbs.

Aside from that, I have also heard the story from a generator guy about the smaller wire/ higher temp = amps the same. I know that from 75-90 degrees at 1/0 wire you get an extra 20 amps in the calculation so it sounds reasonable.

 

[drbond24]

Just because the terminals are rated 105 doesn't mean you are required to use 105-rated wire. It just means that if you use 105-rated wire, you can use the 105-rated ampacity.

If you wanted, you would wire everything with 105-rated wire, but you'd normally be restricted to the 75-rated ampacity because of the terminations. In this case, you are not.

The higher temperature rating just means that the ampacity is higher for a given size of wire.

 

[KevinVost]

i looke at this today...the #12 thhn i bought says on the spool its good for 105 when used for what you described

Thanks for the reminder, a roll of THHN I have laying around says the same thing. I guess I've been out of the working end of the trade too long or I could have suggested it to them :roll:

 

[don_resqcapt19]

Just because the terminals are rated 105 doesn't mean you are required to use 105-rated wire. It just means that if you use 105-rated wire, you can use the 105-rated ampacity. ...

If that is just the terminal rating you are correct, but most of the time the instructions for equipment of this type, calls for the use of conductors that are rated for 105?C. This is because of the heat produced but the equipment may cause the temperature at the termination to exceed that of standard wire. You would not be permitted to use the 105?C ampacity in either case, because the termination at the supply end would not be suitable for 105?C ampacity.

 

[wireguru]

Just throw out my opinion but I don't believe just because the terminal is rated at a higher rating than you wire you are in violation.

On another KINDA related note I once ask a Cummins dealer how he could get away with using undersized wires inside a genset (between generator and gen-mounted OCPD) he told me they used 105 wire and were able to much smaller wires due to the ampacity.

The taps in transformers are like this too. 75kva 480v primary with #10 wire for the taps :roll:

 

[Volta]

i looke at this today...the #12 thhn i bought says on the spool its good for 105 when used for what you described

Just be sure that the temp. is for the THHN rating, and not for the MTW rating. The spool I just loked at allows 105 deg C for appliance wiring. A branch circuit probably can't be wired with a MTW wire/rating per T310.13(A) (2008). Might need type Z.