Ask the Electrician

Hey Alex, I need to change a couple of florescent light ballasts and want to know if it matters which wire I switch first, black or white. Of course I'm doing this hot and will be on a fiberglass ladder.

One wire at a time right? and never complete the circuit = smoking heart...

 

If you absolutely must work hot, always disconnect the hot (black wire) first, and cap it off with a wire nut while you work the rest of the unit.

On a 240v system, it doesn't matter... both the black and the red are carrying 120 with respect to ground, but when you open one, the other one will feed 120 through the device so you have to be more careful.

Disconnect the hot, wire nut, while making sure the wire going to the ballast does not contact ground (in case somebody screwed up on the supply and swapped them), then disconnect the white and wire nut it.

 

IMO an inexperienced person should always shut the circuit off while working, working on a hot 240v circuit is just plain stupid even for an experienced electrician.

 

Agreed.

I'm assuming that it's a commercial/warehouse situation where power can't be killed.

But as a traffic signal tech, we're forced to work hot in a lot of situations that make mere mortals flee... like ankle deep in flowing water in a driving rain storm.
Sucks, and I'm very glad I got promoted out of the maintenance shop.

 

Thanks for the info. gents. Would I benefit from hiring someone who rewires houses as a specialty? Or should all residential licensed electricians have the skill set to rewire a house with AL in it?

 

Get references.

There may be a fair amount of drywall work involved.
I could do it, and it would look like shit unless I subbed out the drywall work, which would add to the cost.

 

That was what I figured. This is going to be a fun project.

 

Hopefully someone can help. I plugged a fan into an outside outlet, it ran for half a second then shut off. I have no more power at that outlet. I plugged it into a gfci outlet, and it tripped immediately. So I gave up on trying to get it going. Now back to the first outlet. I checked the breakers, nothing is tripped. I pulled the cover expecting i fried something in the outlet. But I put my multimeter on the wires coming into the outlet and I have no power there either. Where else can I check to see what is fried.

 

the breaker handle doesn't always go to the off position when tripped, turn the breaker off then back on. if that doesn't work remove the panel cover at meter to see if you have 120V at the breaker.

 

Fixed! The outside outlet is ran through the gfi in my master bathroom. It's reset and I have power again.

 

that's fairly common in older homes.

 

I have 13 years industrial maintenace. I get to do a little of everything - plumbing, pnumatics, hydralics, electrical, electronics, computers, and unclogging toilets . Most of the time, I am repairing something, sometimes I get to do some designing, building and installing.

I sometimes do side jobs for the neighbors ( I have become the neighborhood ceiling fan installer).

The worst thing that has happened to me while working with electricity was getting shocked by an open neutral. I was hired by a company that moved from San Bernadino to Chicago Area. The owners hired some questionable contractors because they wanted the job done as cheap as possable. A sub panel was installed and the neutral was not attached to the neutral buss in the main panel. I was installing a couple breakers in the sub panel and moved some wires to get to the neutral buss and touched it and the ground buss at the same time. The shock was across my hand but felt more like someone hit my hand with a hammer rather than a normal shock. I spent the next 6 months repairing these contractors F ups.

 

Any electricians in the Los Angeles union?

 

I have a problem with my doorbell. Maybe you can help? The damn neighbor kids rang it so much that they broke the button and it would not ring anymore. I replaced the button and it still would not work. It is a lighted doorbell and the light was lit. So I figured maybe the whole thing got fried? I replaced the transformer and the bell. Still nothing. The button is still lit, but will not ring the doorbell. Not sure where to go from here/ Any insight that you could provide would be greatly appreciated.
Thanks

 

Any of you electricians clothes dryer experts?

 

This might be a dumb question for a electrician but can't find the answer. I had a custom house built about three months ago and I had the low voltage guys wire for outside lawn sprinklers but they used Cat5e 24AWG wiring from my garage to my back yard. The Cat5e is run on the interior of my house inside the ceiling and roof covered by insulation. I know it can operate the solenoids on the sprinkler valves through a Orbit brand sprinkler timer with is 24V AC Class 2 power but my question is could the 24V's running through the Cat5e cause a fire or is that very unlikely?

 

Dangerous territory asking electrician's a low volt question.
But I am curious too.

 

I just started as a first year apprentice and I don't know that much but considering 50v and less can't even go through your skin and shock you and cat5 I believe has a shield around the wires and then another one over the group of wires I don't see it being a problem. Then again it's still electricity and even the smallest spark can cause a fire...

 

IIRC Cat5e is rated for 50V.

my concerns would be a) volt drop due to the length of the run b) what's the max current rating of a 4 pair 24AWG cable?

 

24AWG - Enclosed Copper 2.1 amps