ECN Forum Forums General Topics of the Trade General Discussion Area MH High-Bay Lights

It is a 3PH, 4-wire delta-connected system. The high leg (it is a 208V leg)is connected to the 208V tap on the ballast. What other possible use would this 208V tap have? If there's a violation in this installation, please be specific to the NEC, golf junkie.

Dave

Dave,

I'll agree with golfjunkie & CRW here.
The 208 tap off the ballast is for two hots off a 3-phase, 4-wire, 208/120 wye system.
You have a 240/120 delta with the midpoint tap delivering a higher L-N voltage.

BTW,
I believe the reason you see one smaller transformer in a 3-transformer delta bank is because the expected load on the smaller one is less, because of the fact that you shouldn't use the high-leg for L-N loads.
(Utility workers, please verify this ?)



[This message has been edited by Redsy (edited 03-30-2005).]

Forgive me for suggesting the obvious.....but, is the breaker approved for HID use?

Dave:
The situation you explained is:
1: Dangerous
2: Wrong.

Using the high leg for a line-to-neutral circuit is 100% wrong, and dangerous.

The QO CB is rated for 120 volt to neutral/ground, not 200+.

The lights have to be connected either 120 volts, or 240 volts, based on your available voltages. Using 120 volt will result in an approx 2700 watt load, 22.5 amps, and should be on #10, based on 125% for a continuous load.

The high leg is NOT to be used for line/neutral circuit, only line-line (240 volt), single or three phase circuits.

BTW, the QO cb should be discarded in the trash. HID lighting requires a HID labeled breaker. (QO's are usually HID labeled)

John