HVAC OCP Conductor Size

Status
Not open for further replies.
Dennis Alwon

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
The HVAC is equipped with overload protection so that protects the #10 wire. The DP 40 is only there for short circuit and ground fault conditions. So you are not really protecting the wire at 40 amps since the overload protection is rated lower and will protect the wire.
 
augie47

augie47

Moderator
Staff member
Location
Tennessee
Occupation
State Electrical Inspector (Retired)
As to Art 440, I don't have my '14 handy but in '11 you can find the conductor size at Part IV (440.32) and the breaker (SCGF) size in Part III 440.21.
{Justification reverts back to 240.4(G) }
 
Last edited:
Cavie

Cavie

Senior Member
Location
SW Florida
Sparqueee said:
Hello,

Where in the 2014 NEC does it cover being able to install #10 then on @ 40 amp breaker? I have done this before but now can't find the info in 440.

Thank you
Click to expand...

You really don't need a code ref#. The info is on the compressor manufacturer label.
 
kwired

kwired

Electron manager
Location
NE Nebraska
Sparqueee said:
Hello,

Where in the 2014 NEC does it cover being able to install #10 then on @ 40 amp breaker? I have done this before but now can't find the info in 440.

Thank you
Click to expand...
240.3 sends you to 440.

It then gets more complex then for most general purpose circuits because you have short circuit and ground fault protection requirements as well as motor overload protection requirements. But as Dennis mentioned the 40 amp breaker provides the short circuit and ground fault protection and the motor overload(s) protect the motor(s) as well as inherently protect the supply conductors from overload.
 
Status
Not open for further replies.
Top