ECN Forum Forums Photo Discussion Forums Violation Photo Forum 3 phase panel on 1 phase service

Shamefully, I have to admit that I did something very similar to this in my early years in the trade. My boss at the time was very patient with me and allowed me to take on side jobs for friends and family. He would even bail me out if I got in over my head. This time, I really screwed up.

I had some close family friends who owned a lighting supply store. They had expanded and needed to power up an addition of lighting displays. My solution was to install a sub panel for this new display area.

They had a 400 amp, three phase service, and it looked like a pretty straight-forward job. About a 75 foot run of SER cable, another disconnect and the panel was all I needed. This was an old place and the service consisted of a trough with four fused disconnects. I managed to muster up the guts to open the main (and unfused) trough, cut a hole and place another disconnect to feed the sub panel. My boss even came in and tied everything in for me live since I was afraid to do it.

Just as he was finishing, he asked me if I need any orange tape. Being 17 at the time, I asked him "why would I need orange tape, I have white, red and blue"?

I guess you know the rest of the story. It was a high-leg service and the C phase was of absolutely no use in the sub panel. This was my first attempt at working with three-phase services of any kind since all we did was residential. My suggestion was to just skip all C phase spaces in the sub panel, but he insisted that the only way he'd let me do that would be if we cut the third phase completely off at both ends so that it would be impossible to reconnect.

He taught me something very valuable that day and he didn't have to say a word about how I was doing this wrong. He let me make the mistake on my own and pay the price on my own without hardly saying a word. What a great teacher he was. I never made that assumption again and that was nearly thirty years ago.


[This message has been edited by EV607797 (edited 01-08-2007).]

That last story reminds me.....

During my college years I worked at an electronics shop. One day the members of a band comes in complaining about the local bar. Turns out they smoked all their equipment because "the voltage in the place was messed up at 211 volts." I spent an hour trying to find several suitable replacement cube transformers which had smoked. I never thought about it....

Later that year while also employed by a sound and lighting company we arrived at this same bar to set up for a band competition. Upon entering the basement to connect our temp subpanel we notice every other breaker missing and confirmed a high leg voltage of 208 with a VOM.

It was shortly after that I realized the band failed to recognize this oddball service. They also made a major error by not checking the voltage with a meter.

This was back in my hometown and the bar has been there forever. My only guess is the service was left behind from some industrial stuff in the area and they got what the PoCo already had in place.

In retrospect it was strange to see this service...with every other breaker left open.....just waiting for some poor sole.

RSlater,
RSmike