intermittent open on all circuits one bus of panel only

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davef
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intermittent open on all circuits one bus of panel only

Post by davef » Sun Mar 08, 2015 10:50 pm

In my home, when no 240 volt device is drawing current, and the draw is low on all the 120 volt circuits on one bus of the panel; all these lights/plugs will flicker and go out. To restore them, i simply turn on the stove for a few moments or any other 240 volt service comes on and all works well again. All circuits on the other bus of the panel work normally.

This strange behavior occurs usually once or twice a day, but sometimes not for several days.

The hydro power company checked and changed their connectors (so they told me); but their meter is 200' from my house so it's my system from there to my house. Panel is original in home built in 1984.
Electrician says the connections to the meter at the highway look fine, he changed the fuses there on spec.

It's not wind related, or temperature related. The mains hot and neutral wires connections to my main power panel all look ok.

Any suggestions on where to look? the hot side? Neutral? Ground wires? Any testing procedures to suggest? Any recommended connectors to disconnect and reconnect?

thanks, Davef

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Shannon
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Re: intermittent open on all circuits one bus of panel only

Post by Shannon » Mon Mar 09, 2015 7:18 am

Wow, I'm sorry but I have never seen that before. Maybe someone else on here will have a suggestion.
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Aaron
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Re: intermittent open on all circuits one bus of panel only

Post by Aaron » Tue Mar 10, 2015 2:27 am

I can't explain what is going on here, but I can give you some ideas on how to troubleshoot the problem so that you can at least isolate whether the trouble is yours or your power utility's.

You will need a volt-ohm meter to measure the voltage on the line. You should have anywhere between 117-123 volts, that is typical. One leg of your incoming power will vary a little from the other leg, for example one might be 121 and the other 119. But there shouldn't be any more than about a 2% variance from 120 volts.

Have the cover off your panel. Be extremely careful. It goes without saying that you should keep children out of the area, and don't rest any metal objects (screws, screwdrivers) anywhere near the panel when the cover is off. Wear gloves and safety glasses if you have them just in case of any arcs.

If you have vacant breaker openings in your panels, you can easily test the voltage on each bus. Test your volt-ohm meter for continuity first, then set it for a range suitable for 120 VAC. Touch the red test lead on the bus bar the breakers seat into, and the black lead on the neutral terminal bar. Note the voltage reading. Do the same for the other bus. You should have 120 VAC +/- 3V on both legs.

If you are seeing a low voltage reading on one of the legs, then start turning off your branch circuit breakers one by one to see if that changes anything. If turning off one of them suddenly restores the normal voltage on the leg, then you might have a bad branch circuit (either the breaker, the circuit, or some load you have on that circuit).

If after you've turned off all your branch breakers and you still have low voltage coming in, you still need to rule out your MAIN breaker. Keep the breaker ON because you still need to rule it out. If you're in Canada, there may be an additional protective shroud that you need to remove to get access to the service entrance conductors that connect to the main terminals and neutral bus. This is getting into even more risky and dangerous territory because you can not turn off the power that is incoming to the panel, so for heaven's sake, be extra careful.

You will want to measure the voltage at each terminal of the MAIN where the incoming feed is tied down. If there is still the low voltage, turn the MAIN off. Test each again.

If the problem still persists, then your absolute LAST point of troubleshooting is at the demarcation, which is where the consumer's responsibility ends and the utility company's responsibility begins. You may restore the shroud cover (if you had one), and the breaker's cover. Your panel and all its circuits are very likely fine and not the cause of the trouble you're experiencing because you've effectively ruled them out.

I'm not sure about Canada, but in the United States, the point of demarcation is the electrical splice either 1) at the weather head if you have an aerial drop from a utility pole to the property, or 2) inside the electrical meter box if you have buried service.

The rules of whether a property owner has access to this point of demarcation gets pretty murky because you are beyond the electrical panel, and although the consumer actually owns the meter box (but not the meter), the weather head, the wire in the riser to the weatherhead, and/or any buried wire between the meter box and the electrical panel, your access to the actual splice to the utility's supply is inaccessible because the meter box is locked with a tamper-evident device or, in the case of an aerial splice, it's simply unrealistic for the consumer to safely test (they are usually covered in a protective plastic casing that require specialized tools to remove).

So beyond your breaker panel, you will unfortunately require the utility's cooperation in troubleshooting. It's very possible one of their other customers connected to your same step-down transformer is causing an imbalanced load that affects every other consumer connected to the same transformer. Usually they investigate these things if they hear multiple complaints from the same area on their grid.

Your utility should be cooperative in troubleshooting and helping you identify the problem; just know that if the trouble is on your side of the demarcation that they have every right to charge you for the service.

Another simple thing you could try is talking to your neighbors to see if they have this problem too, and if they do, ask them to report it to the utility as well.

Good luck.

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Re: intermittent open on all circuits one bus of panel only

Post by Shannon » Tue Mar 10, 2015 7:17 am

Your the man Aaron! I had no idea what he should even look for.
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Re: intermittent open on all circuits one bus of panel only

Post by Aaron » Thu Mar 12, 2015 12:20 am

I hope he responds back, I'd like to know what the fix was.

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davef
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Re: intermittent open on all circuits one bus of panel only

Post by davef » Thu Mar 12, 2015 11:47 am

Hi guys

No progress on trouble-shooting. The outages last only a few minutes, and most often the family needs the lights back on so we turn on a 240v draw to restore the B-bus house lights/plugs. On the few times i have had family "permission" to leave it off for a while, and go to the panel by flash-light, the @#$% thing self-restores back to normal before i can check the voltages. I want to get out to the demarcation point (200' from my house) and check the bus voltage there when it's down, but timing is never right. (BC Hydro tells be they changed the connectors on their side; neighbors on the same transformer have no problems)

The 40-years-experience electrician who checked my system tells me he changed the fuse on my side of the demarcation point and coated the connections with an anti-corrosive paste, so it's not likely there. He also checked two splice points on the wiring from the highway demarcation to my house and found them ok; and he added anti-corrosive paste. He is baffled as well.

I presume some bus connector or wire that serves all of the B side is corroded/loose/broken and passes current as long as current is high, but becomes open when current is low.

If anyone has ever experienced the "open-when-low-current; closed-when-large-current" phenomena, i'd like to hear about what device/connection it happens with.

I'll post again any progress here.

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Re: intermittent open on all circuits one bus of panel only

Post by Aaron » Sun Mar 15, 2015 1:22 am

Okay, here's something to try. You will need your power company to pull the meter head and kill your incoming power before you can do this!

You may want to be sure your incoming supply lines are torqued down at the MAIN breaker, I suspect you might have a loose connection that's either intermittently open, or it might be oxidized to the point where there is some resistance that might open the connection unless there's a high load. This is actually a dangerous situation because resistance=heat, and heat means potential fire.

Most service entrance cable is aluminum, so if you get the opportunity to re-torque the conductors on your MAIN breaker, be sure to first brush the ends of the conductors with a stiff wire brush or sandpaper to remove loose oxidation. The aluminum should be shiny white. Apply anti-ox paste (you can find this in the electrical aisle of DIY home stores) liberally and work it into the strands of aluminum wire with an old tooth brush. Then torque down the conductors tightly into your main breaker.

The same should be done on the other end of the cable, just for good measure, before power is restored. This is a pretty high-level of troubleshooting and procedure, so if you don't feel comfortable with it, you will definitely want to get help from an electrician.

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Re: intermittent open on all circuits one bus of panel only

Post by emtnut » Sun Mar 15, 2015 9:51 am

Some advice/suggestions

- Try to borrow a 'recording' multimeter (datalogger), or find an electrician that has one. You can place this on the phase you are having trouble with ... The meter will record the incoming voltage. Work backwards until the meter shows no interuption, that will be where your failure is.

- More than likely it is a problem with the HOT conductor, since loosing the neutral would affect both A and B phases. You can verify thou, buy measuring the voltage on the A phase, when you are experiencing a B phase outage. If it rises above 120V, then your problem is with the neutral and very dangerous !

- I wonder about your electrician saying some of the connectors 'looked' good. I have seen many crimp style connectors (ie on the incoming drip loop) fail , but look perfectly fine !

- As Aaron pointed out, this situation can be dangerous, so hopefully you can get to the bottom of this soon !

Wayne
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davef
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Re: intermittent open on all circuits one bus of panel only

Post by davef » Sun Mar 15, 2015 10:54 am

Thanks Aaron and Wayne All this help is greatly appreciated.

Disconnecting 240 volt wires is above my pay grade .... Here's my email to my electrician...
"Hi Henri

I'm still having problems with the intermittent outage on all circuits on one bus of my main panel.

To restore them, i simply turn on the stove for a few moments or any other 240 volt service comes on and all works well again. All circuits on the other bus of the panel work normally.

Sometimes it's for a second or two and clears, and sometimes is for as long as it takes me to get to the stove and turn it on.

As you'll recall, Hydro said they had checked and changed the connectors on their side, neighbours are having no problems, you checked and anti-oxed the fuses at the highway meter and checked connections above the well house and the rooftop splices.

Based on the online forum advise I received (copied below), would it make sense for you to
- open my main breaker
- pull the two big fuses on my side at the roadside demarcation meter
- disconnect the connections at the home main breaker panel, wire-brush the wires, anti-ox paste them, and torque them down good. (or at least do the hot wire, since neutral would like affect both busses)
- If problem not fixed, put on a datalogger and work back to the road looking for the problem before i call BC Hydro again"

Dave Florence

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Re: intermittent open on all circuits one bus of panel only

Post by emtnut » Mon Mar 16, 2015 6:38 am

One other thing I'd run by your electrician, is to change out your main breaker.
It's approx a $70 part, and given it's 30 years old, may not be a bad idea.
Might save you alot of troubleshooting hours.

Just curious.. is it red ? I know Murray breakers had a bad habit of failing !

Wayne
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Re: intermittent open on all circuits one bus of panel only

Post by Aaron » Mon Mar 16, 2015 2:14 pm

That is totally a good idea, Wayne... might as well replace that MAIN breaker.

Hopefully Dave doesn't have a Federal Pacific or Zinsco panel, then the advice would be wholesale replacement.

A

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davef
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Re: intermittent open on all circuits one bus of panel only

Post by davef » Mon Mar 16, 2015 4:08 pm

Hi guys

Problem solved. Turns out it was the main cable crimp connector at the top of the pole on my side of the demarcation meter. Connectors down the line had been checked; seems this one was overlooked.

Thanks for all the advice on this. I learned a lot about the panel in case i have a problem there in teh future.

davef

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Re: intermittent open on all circuits one bus of panel only

Post by Shannon » Mon Mar 16, 2015 4:46 pm

Glad to hear it is all figured out.
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Re: intermittent open on all circuits one bus of panel only

Post by emtnut » Wed Mar 18, 2015 5:17 pm

Glad that everything worked out Dave. Your family must be enjoying 'constant' power !

Aaron, I've heard horror stories about Federal Pacific .. It's Federal Pioneer up here, and although I haven't had any problems with them personally, I wouldn't want one in my home ! Siemens owns it now here in Canada not sure about the US. They still make the stab-loc breaker line though.

Never came across a Zinsco panel up here ! But makes you wonder what garbage the manufacturer's put out there. I'll keep an eye out in case I ever come across one.

Wayne
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Re: intermittent open on all circuits one bus of panel only

Post by Aaron » Thu Mar 19, 2015 11:28 pm

You sure Federal Pacific and Federal Pioneer are the same? I'd be surprised if Siemens ever wanted FP's liability. I know Siemens acquired a company called I-T-E, which actually made the panel that happens to be in my basement.

Zinsco panels are really old, I think, and probably extremely rare if they still exist anywhere in working order. The Federal Pacific ones are just terribly designed, I actually worked on one once and it was just a really janky panel. Really wiggly bus bars, cramped wiring spaces, and just all-around crap.

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Re: intermittent open on all circuits one bus of panel only

Post by Shannon » Fri Mar 20, 2015 7:35 am

There are many Federal panels in my area, but many are being replaced as people renovate because they are over full. Not a great panel design as you said.
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Re: intermittent open on all circuits one bus of panel only

Post by emtnut » Sun Mar 22, 2015 5:39 pm

My bad, it was Schneider that bought them out.
They still make the stab-loc breakers for retros.
Federal Pioneer and Pacific were the same company, but manufactured in Canada and US respectively.
Word has it that the Pioneer older 15 amp double pole breakers have the 'don't trip on overcurrent' feature as well !

This is interesting link for any one with one of these panels

http://inspectapedia.com/fpe/Federal_Pi ... ectric.htm
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