Please check me on this one....

[Bill Smith]

A 90-amp twin breaker fed an HVAC unit of the roof of this condo. The two hots were connected to the breakers in this sub panel. The neutral was not connected to the neutral bus bar. An equipment grounding conductor from that cable was connected to the ground bus. Is the ground carrying the return of the circuit? Doesn't seem right.

[Michael Larson]

Originally Posted by bsmith

A 90-amp twin breaker fed an HVAC unit of the roof of this condo. The two hots were connected to the breakers in this sub panel. The neutral was not connected to the neutral bus bar. An equipment grounding conductor from that cable was connected to the ground bus. Is the ground carrying the return of the circuit? Doesn't seem right.

You'd have to look at the other end in the roof top unit to see in the white is terminated there or not.

The roof top unit doesn't necessarily need the neutral if it doesn't have 120 volt control circuits.

[Bob Elliott]

You do not need a neutral on 220

[Bill Smith]

Thanks guys - I'm rushing between inspections and my brain is a bit twisted. I appreciate the help.

[Speedy Petey]

Like the others said, there is NO "return" in a 240v circuit. This is a line-to-line circuit, as opposed to a line-to-neutral circuit. In fact even 120v circuits have no "return", but that's another story.

A comment on teminology. The breaker in question is a two-pole breaker, or double pole, or 2-pole. It will NEVER be referred to as a "twin" breaker.

The breaker on the lower left IS a twin breaker, at least here in NY. It will get called many things across the country; twin, skinny, cheater, peanut, and more.

[Bob Elliott]

You forgot mini

[mnahrgang]

Question: Would there have been any harm or defect if the Neutral was attached to the buss bar?

[Jeffrey R. Pope]

None whatsoever. . .

[Speedy Petey]

Originally Posted by relliott

You forgot mini

Damn! So I did.

[Marc D. Shunk]

and tandem.

[Gary T. Heller]

Isn't there a requirement for a neutral on any 220 v appliance with a 120 volt circuit?

[Marc D. Shunk]

Originally Posted by gheller

Isn't there a requirement for a neutral on any 220 v appliance with a 120 volt circuit?

Functionally, it needs one, but there's no requirement. The equipment could just as easily have a transformer built into it for the 120V loads. Commercial laundry equipment and rooftop air conditioning units often do have a 240x120 control transformer. There is a general prohibition against using the neutral and jumpering it to also serve as the equipment ground, as was once done with ranges and dryers.

[Speedy Petey]

Originally Posted by gheller

Isn't there a requirement for a neutral on any 220 v appliance with a 120 volt circuit?

Yes, but then it would not be a 240v appliance. It would be a 120/240v appliance.

Like Marc said, this generally applies to household cooking appliances and dryers.

[Speedy Petey]

Originally Posted by Marc D. Shunk

and tandem.

OK, leave me alone.