Hot tub derating

[daiashi]

How to derate wire for 75c hot tub terminals?Thanks

 

[celtic]

How to derate wire for 75c hot tub terminals?Thanks

Need a little more info.

Why are you derating what type wire?

 

[daiashi]

Have always ran #8 thhn in 3/4 conduit.However now local inspectors
are requiring #6 because of the heat build up with #8. on 75c. Terminals.

 

[infinity]

If the terminals are rated for 75 degrees then you can use the #8 THHN protected at 50 amps. What size OCPD are you using?

 

[haskindm]

Use the ampacity from table 310.16 for 75 degree conductors.

 

[daiashi]

If the terminals are rated for 75 degrees then you can use the #8 THHN protected at 50 amps. What size OCPD are you using?

I am using a 50 amp gfi breaker.I don't know where the inspector is getting
his info however he or she is creating an unnecessary expensive.Thank you.

 

[raider1]

If you are using a 50 amp breaker and all the terminals are rated at 75 degrees C then you can use #8 THHN copper conductors.

The inspectors might be tring to use 110.14(C)(1)(a)(2) to say that you must use the 60 degree C column to get you ampacity. Show them 110.14(C)(1)(a)(3) this allows you to use the 75 degree C ampacity column as long as the wire and all the terminations are listed and identified for use at 75 degrees C.

Chris