AFCI Questions

Ballvalve · Jan 17, 2012

Heres a good one for fiberglas ladders and gloves. My guy had a dustcollector to remove. Got it running and shut off the breakers until it went off. On later inspection after his dikes were welded shut, discovered that some nut had brought in a hot line off another circuit and wired it in through some bizarre set of relays. Killed the motor with one line only, and nearly killed a guy that should have tested the teminals first.

ActionDave · Jan 17, 2012

romumok said:
On the side note, yesterday I had a first hand experience with the effectiveness of AFCI breaker. I was installing a new light fixture, the way this particular fixture was wired is power -> switch -> light fixture So with the switch off, I did not have power at the fixture so I proceed to installed the new fixture. The electrician ran the new NM cable a bit too long so I decided to shortened a bit. But before, I did that I made sure that i did not have any power by probing with the non contact probe. Once checked, I proceed to cut the NM cable. As soon as I made the cut, the light in this particular circuit went off almost instantly. Wondering, why have happened I decided not to reset it after finishing installing the light fixture.
.

Where was the arc? The breaker tripped because there was contact between the neutral and the ground- a neutral to ground fault.

Sponsor · 2022-01-29T12:20:58-0800

Romumok · Jan 18, 2012

There were no arc. After thinking about it, I should have said fault to ground. I guess I was going with what the info found in the box.

Kreemoweet · Jan 18, 2012

DonL said:
Most of them non contact meters can not read the voltage unless there is current on the line.

If the breaker or line under test is Off, or not drawing current, they are useless.

This is not true at all. I've had maybe a half dozen different brands of those things over the years, and not a single one has
required current in the wires to detect line voltage. (Actually, there is ALWAYS a tiny amount of current in any AC-energized
conducter, but that I am sure is not what was meant.) I also have NEVER had a false negative reading (when the voltage was
within specs, and the battery was not dead. Lots of false positive readings, though.

DonL · Jan 18, 2012

ballvalve said:
Heres a good one for fiberglas ladders and gloves. My guy had a dustcollector to remove. Got it running and shut off the breakers until it went off. On later inspection after his dikes were welded shut, discovered that some nut had brought in a hot line off another circuit and wired it in through some bizarre set of relays. Killed the motor with one line only, and nearly killed a guy that should have tested the teminals first.

I short the line out, then you know the power is really dead. I don't even trust a Voltmeter. Anything above 120V is a very shocking experience. 120V can kill, but 480V or 600V kills you faster.

Lets not forget Lock out-Tag out..

AFCI Questions

Users who are viewing this thread

Ballvalve

General Engineering Contractor

ActionDave

Electrician

Sponsor

Paid Advertisement

Romumok

New Member

Kreemoweet

In the Trades

DonL

Jack of all trades Master of one

Similar threads