ECN Forum Forums General Topics of the Trade General Discussion Area choke on this

I still get amuzed by the number of electricians I meet on the job that don't realize you can't run seperate phases to the same three phase load in seperate conduits.
I've had to explain the concept of building a "choke" to more guys than I can shake a stick at.
It's almost as bad as the concept of splicing copper to aluminum in a split-bolt without the divider.
Anyone else have anything to add about this?

Lamplighter, actually you can do this if you are using non-ferrous wiring methods and the conditions of 300.20(B) are met.

Roger

I wasn't aware of that but, I've never been in a position where that would come into play either.
I have seen the effects of trying to do it in rigid metal conduit and it wasn't pretty.

There is nothing wrong in learning something new, we all do this from time to time. With me the times in between are real short.

One of the hardest things that I had to learn when starting out as a green horn was just where I was at.

It seemed that I was never just where I was supposed to be and was getting yelled at due to this fact.

Well one day I just ask the boss, “Just where am I supposed to be?”

He answered me with this.

If you are not here and you are not there then you have to be somewhere else. Now get over yonder where you are supposed to be. That was thirty seven years ago and the truth be know, I am still lost.

The company I work for recently repaired a job that the feeders for large RTUs where run in an isolated phase fashion. From the guys there they said it was quite an impressive meltdown.


A large underground service run in PVC is not unusual in my area.

Any chance they took some pics?

One of the best melt downs I've ever seen was in a holiday in that we had as a customer.
The maintanance man for the hotel was supposedly going to tighten the lugs on the main, he threw the switch to "off", opened the door, and stuck his bare metal allen wrenck into the lug.
The mechanism supposedly allowed him to open the door without actually shutting down the power.( most likely he used his screwdriver to trip the latch and hadn't really shut it down.)
The lugs were hot, he took a 480v hit, dropped the wrench into the gear and ended up blowing a 3'x5' hole in the F.P.&L. vault wall.
We showed up and overnighted a new switch in from Alabama or someplace. striped the old out, installed new and got the 400 unit hotel back on line in 36 hours.
Damn I was tired!
The maintanance guy survived but,last I heard, was starting to have digestive problems and trouble walking.

>>The maintanance man for the hotel was supposedly going to tighten the lugs on the main, he threw the switch to "off", opened the door, and stuck his bare metal allen wrenck into the lug...<<

no wiggy check? stupid is as stupid does...

... Sounds like a candidate for the Darwin Award to me.... I feel bad for the poor yutz!!
Russ

Any of you guys hear about the guy who tried to check a 13.2 line with his wiggy a year or so ago?
He didn't live to learn his lesson.
May have only been broadcast on local news.