Unacceptable voltage drop

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electricaldoc

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I have been having a lot of problems with dimming lights every time load added. I live in a mobile home, which I know uses 14awg for lighting circuit. I also know this is to code since on 15A breaker, but causing VD problems. My digital meter will not detect it, but my new GFCI, ACFCI analyzer will. I come up with 6.3% VD on one circuit and 8.7% VD on the other. Also my true rms voltage drops from 121v to 116v when wife turns on blow dryer, which is not even on same circuit. Power Company said their side fine. All loads are balanced on each phase. I have checked out all connections none loose.

So is there any way to correct problem, without rewiring all lighting circuits?
 
Re: Unacceptable voltage drop

What is the open circuit voltage with loads off?
Are there other loads running when you test?
The volt drop seems excessive. What size service and how far from the transformer?
 
Re: Unacceptable voltage drop

This sounds like a loose neutral. Main panel box or in your meter box. If the electic company said that they are OK then check what I wrote. Now if you have a voltage drop without a load then I would again check the meter and the main panel box. If they seem OK I bet you that it's a loose neutral on the electric company's side.
Bye now,
Jim
 
Re: Unacceptable voltage drop

Dan:

Have you tried to rearrange the circuits in the panel. If you can move all of the high load circuits to the top or close to the Main and then move down the panel might be a step in helping this dimming issue. I have seen this help in situations like this in the past.

Good luck

Norb

[ June 06, 2005, 10:19 AM: Message edited by: 1793 ]
 
Re: Unacceptable voltage drop

I have seen this exact problem on double and triple wide mobile homes. You can check everything available and no loose connections. If the voltage drop is on a circuit that is on the opposite side of the house verses the panel it is usually a connection underneath where the two sections of house are attached together. Sometimes these splice boxes can be difficult to find or reach so if this is the case you may have to run a new line under the house from the panel to the existing circuit.

Also I have found on a lot of mobile homes that they like to use all back stab wiring for outlets which can sometimes cause a voltage drop situation due to poor connections.
 
Re: Unacceptable voltage drop

The voltage drop is with only lights on, or even with AC running. I notice that the ones, with very low VD have 0V Neutral to ground. The ones that have high VD have about .35V neutral to Ground. I just checked all receptacles and 20A are all fine, but the 15A are bad. The one in master bath has a VD of 15% according to analyzer. This tells me to start checking connection on all outlets in lighting circuit.

Also does any one know how these analyzers test VD? This could possibly help me to understand where to look.

Thanks every one
 
Re: Unacceptable voltage drop

Originally posted by 1793:
Dan:

Have you tried to rearrange the circuits in the panel. If you can move all of the high load circuits to the top or close to the Main and then move down the panel might be a step in helping this dimming issue. I have seen this help in situations like this in the past.

Good luck

Norb
Click to expand...
Im curious to find out how moving breakers from bottom to top of main panel helps correct voltage drop or any other high load situation? Im not being a smart *** , im just curious and want to learn. :D
 
Re: Unacceptable voltage drop

If high load circuits are at the bottom of the panel, when they kick in the draw through the panel to that point can cause a drop (dimming) to the circuits ahead of them. Think about the initial pull of power, for an instant the lights dim. If the draw is constant then the dimming will last as long as the load is present. I always try to put high loads at the top and work my way down, 20 amp circuits next and 15?s at the lower end.

I hope this helps and I'm sure others will chime in. Sorry I don?t have a good illustration for this.

Norb
 
Re: Unacceptable voltage drop

Norb IMO the arraignment of the loads in the panel is of little consequence.

All current still flows to the panel via the same feeder / service conductors. A few inches of bus bar will be irrelevant.
 
Re: Unacceptable voltage drop

You mentioned that voltage drops when load is added to a DIFFERENT branch circuit. This could be a problem with only say 1/4 of the wire strands in the service or feeder carrying electricity.

If you get enough copper oxide or aluminum oxide in stranded wire you will have say a 25 amp wire instead of a 100 amp wire. This is the single biggest power quality problem that I see in old buildings.

I have also seen this problem with #12 solid copper wire where copper oxide creates quite a bit of voltage drop. It also turns out that Dr. Jesse Aronstein ran some tests that 5 or more wires in a Scotchlok(R) or Wirenut(R) is asking for problems and my experience bears this out. The only time that I put 5 wires into a Wirenut(R) is when it is a thermostat circuit in #18 wire where the maximum current that there can be is 3 amps or less.

In any of these cases you need to take apart your wiring connections and clean them up with #220 silicon carbide abrasive paper. I have a white paper on how to do this without cutting your fingertips over at http://home dot earthlink dot net/~mc5w .

I also encountered an instance where a slightly corroded fuse clip caused a motor to run partially single phase causing the motor to burn up. In instances where somebody is nuisance blowing fuses for a central air conditioner this is one of the first things that I check. A lot of times one of these issues is the problem.
 
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