tyha
Senior Member
- Location
- central nc
Is it permissable to use a #10 neutral for a air handling unit on a 35 amp 3p breaker. the 3 phase wires will be # 8. min cir amp for unit is 27.3 max ocpd is 40.
Obviously, if there is a neutral terminal, a neutral connection is required. However, most line-to-line equipment is equipped with a transformer with a suitable primary voltage.tyha said:The neutral is required due to control voltage for the thermostat.
FWIW - Many air handlers have an internal service receptacle--which requires a neutral.LarryFine said:Obviously, if there is a neutral terminal, a neutral connection is required. However, most line-to-line equipment is equipped with a transformer with a suitable primary voltage.tyha said:The neutral is required due to control voltage for the thermostat.
Interesting; never seen one, but you'd be correct, as long as it's ahead of the unit disconnect.Smart $ said:FWIW - Many air handlers have an internal service receptacle--which requires a neutral.
The one's I've seen have been and of those, the equipment had an integral disconnect in the form of a 3P breaker with one phase of line side tapped for receptacle via OCPD.LarryFine said:Interesting; never seen one, but you'd be correct, as long as it's ahead of the unit disconnect.
The tap had it's own OCPD ahead of the receptacle.Pierre C Belarge said:If you are tapping on the line side of the disco, that is permitted. There are limitations though, due to the size of the overcurrent device supplying that circuit. If the circuit is rated 30 amps or larger, than that will preclude tapping that circuit for the receptacle that supplies a 15 or 20 ampere rated receptacle - 210.21(B)(3).
I've seen those types, too... in addition to ones that don't have any!Pierre C Belarge said:I myself have not seen this receptacle that is integral with the A/C equipment tapped off the line side of the disconnect, but I have seen them where a circuit is installed to them, or there is a small transformer in the enclosure to supply them (usually 277/480v supplies).
Not necessary, but thanx.tyha said:Larry, I do apologize for my response.
I don't have the exact code sections in front of me, but it's based on the fact that almost all HVAC compresors have internal current-limiting/overload protection.Where can I site that I can use #10 for the entire circuit.