How far should I run when power is turned on?

[peter]

We are nearing completion of a large, 160,000+ sq. ft. home improvement box. This other guy, Juan, is connecting the main panel. It has six parallel feeds of six 500 kcml cables for each phase.
For some reason, he tested the bus bars with his meter and found zero resistance between Phase A and Phase B. What could cause this? :roll:
So how far should I be from this thing when it is energized?
~Peter

 

[dereckbc]

Re: How far should I run when power is turned on?

I wouldn't run. I would make sure I was at least 100 feet away before he energized. Make Juan turn it on.

Seriously, you need to find the problem, it could be anything from improper wiring, mis-labled cable, etc.

 

[bennie]

Re: How far should I run when power is turned on?

Make your partner turn this on. You may make a hole in Juan

 

[roger]

Re: How far should I run when power is turned on?

Bennie,

You may make a hole in Juan

that's priceless.

Roger

[ August 27, 2003, 04:03 PM: Message edited by: roger ]

 

[hillbilly]

Re: How far should I run when power is turned on?

Continuity is the word. Could be as serious as a short circuit, could be as simple as a water heater thermostat calling for heat. Kill all of the branch breakers and check it again.

 

[karl riley]

Re: How far should I run when power is turned on?

Hey Bennie, is your first name Jack?

Karl

 

[brian john]

Re: How far should I run when power is turned on?

Peter:

I often here about electricians using 2X4's pipes ect........ to turn on main switches.

While I use extreme caution and required safety measures I have never felt it was necessary to RUN when energizing a service, switchboard, MCC, etc. There are procedures for proper testing prior top energizing switchboards and/or services. I can not imagine energizing a service without testing the line and load conductors.

This includes the neutral conductors (they will need to be isolated).

 

[peter]

Re: How far should I run when power is turned on?

Problem solved!
There is a small transformer in the outside cabinet fed from phases a and B. This was disconnected, tested and there was no continuity after that.
This is a 2000 amp panel for a big box store -- that is a Lowe's.
Thanks for the replies.
~Peter

 

[jrdsg]

Re: How far should I run when power is turned on?

continuing a thought from another thread...

would it be possible to use a tdr [time domain reflectometer] to find out how far from the test point the continuity [analogous to a short] is located? if so this would give one the radius from the test point at which the problem would be found.

we do this on the low-voltage side of things to find crossed wires, shorts, opens, etc.

 

[tom baker]

Re: How far should I run when power is turned on?

Peter, now you know. But there is a valid reason to test insulation resistance prior to energizing, of course with the loads or transformers disconnected.

 

[brian john]

Re: How far should I run when power is turned on?

Tom:

And more than likely that transformer powers Ground Fault Protection for the switchboard and if they did not test the switchboard, neutral ground, they probably did not test the GFP.


Just a guess!!!!!!