What would cause lights to shut off when pressing a dryer start button AND MORE!!?

[sparky_chick]

My friend is having some major electrical issues at her house. When you turn on a light others dim or turn off. Also, if you hit the start to the dryer, it shuts off the light. This issue is not isolated to just one circuit, it effects the entire house. Any ideas?

 

[jumper]

First guess-bad neutral.

Can you check the voltage?

 

[sparky_chick]

Yes, voltage phase to ground is 115 and phase to neutral is 115.

 

[jumper]

Yes, voltage phase to ground is 115 and phase to neutral is 115.

You get these readings at each breaker with a load?

 

[GoldDigger]

Yes, voltage phase to ground is 115 and phase to neutral is 115.

And that measurement is for both line conductors and with a heavy load turned on?
If so the problem(s) are downstream of the panel.
Measure then at the receptacles.

 

[jumper]

Yes, voltage phase to ground is 115 and phase to neutral is 115.

220-240 Line to line?

 

[Ponchik]

Using a wiggy (solenoid tester) check the voltage at the main panel right after the main breaker. Check for 120V, 240V. If you don't have a wiggy then you can use a DVM and couple of incandescent light bulbs when doing this test with the bulbs connected to A & N and B & N.

Same as above check the voltage at the sub panel.

Have your friend turn all of light ON or turn on couple of hair dryers (on different circuits) then check for voltage at the main panel.

 

[sparky_chick]

That was with no load. I am not currently at their home. I went up on saturday and ran out of daylight, but what i did find while i was there was, they have a 125A main service w. meter. It appears as though they have a 70A breaker that goes approx. 150ft. underground to a 200A panel at the main house. Phase to Phase was 220 ish, (i forgot to write down that value). I plan on going up again with a thermal imager and ohm meter to check the wire insulation. I don't understand why they would be feeding their entire home off of a 70A breaker.

 

[sparky_chick]

I have a wiggy and a amp meter and access to ohm meter and thermal imager

 

[GoldDigger]

You should not need the thermal imager unless you have to find a glowing connection inside a wall.
A 70A main is not out of the question for a small old house. But it might also be a split bus with two feed breakers or other weirdness.
Be sure to have a heater, hair dryer or other portable load. Maybe with a long set of extension cords so that you can turn it on and off while standing at the panel.
If the circuit with the lights has no receptacles, you can measure at the breaker and if necessary open up a luminaire or screw in a receptacle adapter.
If all if the lights are on one circuit, look for a bad neutral on that circuit or s high resistance hot.
The wiggy is great for finding open circuits, but the DVM is more sensitive for voltage drop.
It does not seem at all like an insulation problem, BTW.

 

[cowboyjwc]

Check the main breaker, you probably have a phase out.

 

[sparky_chick]

You should not need the thermal imager unless you have to find a glowing connection inside a wall.
A 70A main is not out of the question for a small old house. But it might also be a split bus with two feed breakers or other weirdness.
Be sure to have a heater, hair dryer or other portable load. Maybe with a long set of extension cords so that you can turn it on and off while standing at the panel.
If the circuit with the lights has no receptacles, you can measure at the breaker and if necessary open up a luminaire or screw in a receptacle adapter.
If all if the lights are on one circuit, look for a bad neutral on that circuit or s high resistance hot.
The wiggy is great for finding open circuits, but the DVM is more sensitive for voltage drop.
It does not seem at all like an insulation problem, BTW.

I won't know if there is a glowing connection inside a wall unless i have the thermal imager

So, a bad neutral on one circuit will effect the whole house circuits?

 

[cowboyjwc]

I won't know if there is a glowing connection inside a wall unless i have the thermal imager

So, a bad neutral on one circuit will effect the whole house circuits?

See my answer. That will affect the whole house. Check ground to each phase and phase to phase. With a bad neutral the lights will usually get brighter when a load is added.

 

[GoldDigger]

See my answer. That will affect the whole house. Check ground to each phase and phase to phase. With a bad neutral the lights will usually get brighter when a load is added.

But with an open phase, the lights are more likely to go on than go off when a 240V load is switched on! With no 240V loads connected, any lights in the open phase will not work at all.
A transformer primary wired line to line (maybe a control transformer in the dryer?) would allow a limited amount of load on the dead phase, and that phase to ground would measure ~nominal voltage. Line to line would measure near zero.

 

[jeepx]

If you have not already I would start at the Mb tighten all connections line and load paying extra attention to neutral s and do the same at house panel if all looks well I would turn on one or two lights have some one watch the lights as I smacked the service drop connections with a 2 x 4 if lights flicker it is most likely a utility connection at the service drop

 

[ActionDave]

I'm going with lost phase. Since there is inderground wires involved it may not show up with just a voltmeter check or even a wiggy. Put a load on and check main lugs at service and sub panel .

 

[cowboyjwc]

But with an open phase, the lights are more likely to go on than go off when a 240V load is switched on! With no 240V loads connected, any lights in the open phase will not work at all.
A transformer primary wired line to line (maybe a control transformer in the dryer?) would allow a limited amount of load on the dead phase, and that phase to ground would measure ~nominal voltage. Line to line would measure near zero.

That might be true, but again the lights wouldn't go off with a open neutral either, they will usually get brighter when a load is applied. Simple test to see if there's an open phase and if it shows up at the main then you need to pull the meter to see if it's on the utility side or the load side.

 

[electricalist]

When I come across these type problems I start at the panel. Tighten the neutrals and check phase to phase ,phase to neutral and phase to ground. Turn everything off in the panel except the circuits with the problem. It sounds novice I know but I have found 2x wires landed on wrong breaker. Ie 30 a ac , 1 phase on hot water breaker. Anyway if voltages look good then I'd refeed the problem lights at the switch from a circuit as close to the panel as I can. I believe the lights will work when you do that and not shut off.. This could mean there's a bad neutral by loose connection or I think not a real neutral

 

[kwired]

Could be bad neutral, could be bad ungrounded conductor.

Do you read ~240 volts from ungrounded to ungrounded?

Are there any 240 volt appliances, if so do they work?

Does the dryer start, or attempt to do anything when you press the start button or does lights you mentioned just go out and nothing from the dryer?

Troubleshooting hint involving the dryer: most electric dryers have 240 volt heat elements but the motor and controls are 120 volts. The heater is interlocked with a centrifugal switch on the motor and it will not heat unless the motor is up to speed and the centrigugal switch is closed, so pressing start button is not closing a 240 volt circuit it is closing the 120 volt motor circuit, the 240 volt heater can only be placed on the system after the motor does start.

 

[James L]

I ran into a scenario like this a few years back. In the panel there were two neutral bars. The neutral from the meter was landed in the bar with most of the circuit neutrals landed in it. But there was a second, isolated bar that was not bonded to anything.

The dryer circuit was a 2-wire w/g, and the bare ground was landed in this 2nd isolated bar. There were also 4 circuit neutrals landed in this isolated bar. Those circuit hots were all on the same leg. The bare dryer ground was laying along the side of the neutral bar, barely touching it.

The 4 circuits were getting a faux neutral from the bare dryer ground laying alongside the neutral bar, barely touching it. Every time the dryer got turned on, the bare ground apparently lost its feeble "connection" alongside the neutral bar. Vibration, maybe? I dunno. But every time that dryer got turned on, those 4 circuits went out

Anyway, I ran a jumper from the neutral bar to the un-bonded bar and that solved it