AWG needed for 68.5 amp 240 vac?

[Bill C]

Hello,

Can someone please tell me what AWG copper line is required to service a
68.5 amp 240vac tankless water heater? The manufacturer recommends an 80 amp breaker.

Thank you

Bill

 

[TURTLE]

Hello,

Can someone please tell me what AWG copper line is required to service a 68.5 amp 240vac tankless water heater? The manufacturer recommends an 80 amp breaker.

Thank you

Bill

there is all kinds of type wire to choose from as distance of run and as in conduit or not and you can run it in # 6 to a # 2 by just what type wire it is and the metal the wire is made out of.

So if run in Copper wire run # 2 and you can't go wrong. the wire can be smaller if you tell the conditions like length of run , type of wire you have to use , and in conduit or out.

TURTLE

 

[Doug Miller]

Can someone please tell me what AWG copper line is required to service a
68.5 amp 240vac tankless water heater? The manufacturer recommends an 80 amp breaker.

Anywhere between #6 and #2. Depends on the temperature ratings of the conductors, and how they're installed (cable, conduit, etc).

 

[RBM]

There are variables but generally for what you're looking to do, number 4 THWN

 

[Bill C]

Thanks everyone. I don't like my subpanel setup. It's a big mess to upgrade and a long run in an old house to try to pull new wire. I'll just replace this failing tank water heater with another tank water heater.

Regards
Bill

 

[Stormin Mormon]

Also, copper versus aluminum makes a difference. I don't have a spec sheet, but alum takes a lower number. Which is a physically larger wire.

Can someone please tell me what AWG copper line is required to service a
68.5 amp 240vac tankless water heater? The manufacturer recommends an 80 amp breaker.

Anywhere between #6 and #2. Depends on the temperature ratings of the conductors, and how they're installed (cable, conduit, etc).

 

[zxcvbob]

Also, copper versus aluminum makes a difference. I don't have a spec sheet, but alum takes a lower number. Which is a physically larger wire.

He needs ampacity of 85A rather than 68.5 because it's a continuous resistive load. #3 Aluminum type SE cable will work if the breaker and terminals are rated for 90°C. Otherwise, he needs #4 copper rated for 75°C or better.

Best regards,
Bob