DIY Chatroom Home Improvement Forum

DIY Chatroom Home Improvement Forum (http://www.diychatroom.com/)
-   Electrical (http://www.diychatroom.com/f18/)
-   -   wire mess :( (http://www.diychatroom.com/f18/wire-mess-166388/)

gavman 12-13-2012 05:49 PM

wire mess :(
 
I am maintenance man for a beat up old hotel and the wiring is a mess!

I am not an electrician but can do minor repairs but just can't figure this one out... I have one room that has power to the switches, plugs and light but when I plug anything in, it doesn't work.
same with the lights. I flip the switch and nothing. both the black wire and white wires have power to them in all the lights, plugs and switches. what's wrong ?? also, the exit sign right outside the door to the room must be on the same circuit because it has the same problem and we really need that sign to work!

I unhooked the sign and checked it elsewhere and it works fine. when I hooked it back up it came on for a cpl seconds then went out...HELP PLEASE!

Dave632 12-13-2012 06:00 PM

Quote:

Originally Posted by gavman (Post 1072518)
I am maintenance man for a beat up old hotel and the wiring is a mess! I am not an electrician but can do minor repairs but just can't figure this one out... I have one room that has power to the switches, plugs and light but when I plug anything in, it doesn't work. same with the lights. I flip the switch and nothing. both the black wire and white wires have power to them in all the lights, plugs and switches. what's wrong ?? also, the exit sign right outside the door to the room must be on the same circuit because it has the same problem and we really need that sign to work! I unhooked the sign and checked it elsewhere and it works fine. when I hooked it back up it came on for a cpl seconds then went out...HELP PLEASE!

How do you know the circuit(s) "have power"? If you're using a multimeter and reading the voltages, you're probably reading what is called "phantom voltage". This is voltage that isn't coming from the service panel, but rather is induced in the wiring by current flowing in adjacent wires. When you plug in a real load (like a light bulb), the induced current is too low to light the light.

Can you find the breaker that serves that room? Does the breaker serve any other rooms? Do the outlets in those rooms work (actually power a light, for example).

Starting at the breaker, work your way to the room, testing as you go. The problem will be between the last test point that has power and the first test point that does not.

gavman 12-13-2012 06:09 PM

I've just started working here and they have nothing for meters and such. all I have is my little tester light ithat lights up and buzzes when I touch the wires or the plugs. this is the very last room at the end of the hall. all the other rooms seem to be fine. the panel is way at the other end and I have no idea what breaker is for what as nothing is marked. this might be more than I can deal with but we are waaaay north on the Alaska hyway and we are very rural. hard to get an electrician up here.. thank you for your reply Dave. I'll try to figure it out

gavman 12-13-2012 06:14 PM

I didn't think I'd be dealing with this kinda thing. I thought maybe change a few switches or plugs but not this kinda problem. this place is off the grid and is run via generators. the last owners of this hotel did some pretty crazy things with the electrical and plumbing. I'm sure I'll have lots of question about both :(

mpoulton 12-13-2012 06:33 PM

You need a real meter to do any electrical work. Non-contact voltage testers are good for some things, but cannot be relied on for anything important - like making sure a circuit is dead and safe to work on. You said that BOTH the black and white wires "have power". That is not normal and suggests an open neutral. Since the entire circuit seems to be affected, check the circuit's neutral connection in the panel. If that's not the culprit, then check the neutral connections in every J-box on the circuit until you find the problem. Of course, you really need an actual meter to do any of this.

Jim Port 12-13-2012 06:45 PM

The circuit can have power, but without the return path provided by yhr neutral you will not have a complete circuit and nothing will work.

AllanJ 12-14-2012 10:45 AM

There could be a loose connection somewhere that will pass enough current for a meter to read 120 volts but when you turn something on or plug something in, the loose connection has so much resistance that much of the 120 volts is dropped there and reduced voltage is seen at the light or appliance. (The loose connection can also heat up enough to start a fire since many watts, which is volts times amperes, can be dissipated there.)

(slightly off topic technicalia follows)

At all times, in any portion of a circuit, the voltage between the "entrance" and "exit" wires is equal to the number of amperes going through times the resistance of that portion (Ohm's Law). If 100 volts were dropped in the section with the loose connection then only 20 volts remain to power the light which will glow dimly or not at all. Under normal conditions, the paths (hot and neutral wires) have negligible resistance and the full 120 volts (or 118-1/2 volts if you insist, 1-1/2 volts dropped within the wires as an example) is available for the light or appliance.

A meter draws very little current, milliamperes at best. So even a very dirty or loose connection that is not completely severed might drop only a few volts at 10 ma (150 ohms of resistance and 10 ma of current means a 1-1/2 volt drop) and the meter registers close to 120. Meanwhile a 100 watt light bulb draws about 0.8 amps and has a resistance of about 150 ohms. With both the light and the loose connection in the circuit the total resistance is 300 ohms half of which is the loose connection so the loose connection drops 60 volts and the light gets 60 volts. Given 120 volts across 300 ohms the current draw is 0.4 instead of the previously mentioned 0.8 but still enough watts (60) are dissipated in the loose connection to possibly start a fire. (Not exactly correct since the light bulb has a lower resistance when it does not reach full brightness and internal temperature, but you get the idea.)

tylernt 12-14-2012 01:53 PM

Quote:

Originally Posted by gavman (Post 1072526)
we are waaaay north on the Alaska hyway

If you are in the US, then usually the only time you don't need to be a licensed electrician is when you are a homeowner working on your own home. Are you sure it's legal for an unlicensed person to do electrical work on a commercial and/or multi-unit dwelling such as a hotel?

I don't mean to cast aspersions on your abilities gavman, I'm just a little worried about the legal liabilities. Hate to see you get arrested or sued if someone got hurt, even if it's not your fault. I realize you are off-grid, but the NEC and federal laws still apply to generators.

jbfan 12-14-2012 02:04 PM

Quote:

Originally Posted by tylernt (Post 1072982)
If you are in the US, then usually the only time you don't need to be a licensed electrician is when you are a homeowner working on your own home. Are you sure it's legal for an unlicensed person to do electrical work on a commercial and/or multi-unit dwelling such as a hotel?

I don't mean to cast aspersions on your abilities gavman, I'm just a little worried about the legal liabilities. Hate to see you get arrested or sued if someone got hurt, even if it's not your fault. I realize you are off-grid, but the NEC and federal laws still apply to generators.

Not true for all states.
In GA, you are required to be licensed only if you contract electrical work.
I can work in any industrial, or commercial place, do work and be fine.

mpoulton 12-14-2012 03:10 PM

Quote:

Originally Posted by tylernt (Post 1072982)
If you are in the US, then usually the only time you don't need to be a licensed electrician is when you are a homeowner working on your own home.

Most states (I don't know of an exception off the top of my head) allow facilities maintenance personnel to do electrical repairs under most circumstances.


All times are GMT -5. The time now is 09:01 PM.