I have a house that was built in 1900. Wiring has been replaced with romex. Service panel is a GE PowerMark Gold 150-amp with all disconnects 20-amp and up. The first service disconnect is on the exterior, under the meter. The neutral and ground bus bars are bonded with a bar at the bottom. I see no green screw.
I have a new Hotpoint washer which calls for a 15-amp disconnect; no voltage is specified on the dataplate, which would seem to imply that anything from 110 volts to 130 volts is acceptable.
Whenever the washer is running, the lights resonate brighter and dimmer once every second or so, to the cadence of the agitator working forward and back. When the dryer is also running at the same time, the lighting throughout the house pulses double-time.
I observed that I get a different voltage reading on the output terminal of different disconnects. Some read 120 volts; others read 125 volts.
Does this suggest a grounding problem? Should the bonding bar between the neutral bus and the ground bus be removed, as the main disconnect on the exterior of the house is already earth-grounded?
It could be any number of things including a bad neutral. By disconnects are you referring to circuit breakers? Did you check the voltage at the service disconnect on the outside at the incoming line side terminals? Do you have some photo’s that you can post of the inside and outside equipment?
Yes, Robert, thanks. Service panel disconnects = circuit breakers. I attempted twice to load photos. But bad reception where I am now. Will do so later.
No problem.
Most likely a loose neutral somewhere, including the possibility of the service neutral. This same thing happened to me a couple years ago, I checked every neutral in the panel, and the receptacles for that circuit, and it ended up being a disconnected neutral at the pole!! But yet it was only noticeable when the washing machine was agitating, and almost every light in the home was dimming.
Not a ground issue.
Point of Termination.
Question: How far away is the distribution panel from the laundry room?
Is the washer dryer on lighting circuits? Should be on dedicated circuit.
This one stumped me, but I found a thread about a fellow who had this issue with a different unit:
Question. Are lighting circuits rated at 20 amps and not your typical/usual 15 amp or are your referring to equipment circuits? Lighting Circuit cables/conductor and OCPD’s don’t jive. Could be an issue with over fused/breaker cables.
Lighting circuit cable/conductors AWG is 14 for lighting switches and receptacles so switches and receptacle must be rated for 20 amps. 20 amp receptacle would look like the imaged posted.
20 amp switches are about 10x’s the cost of 15 amp switch.
Be sure your images are JPEG.
I use Windows snipping tool.
Select the Start button, type snipping tool in the search box on the taskbar, and then select Snipping Tool from the list of results.
1: Copy an image and save to your photo folder.
2: In the menu bar, hover your courser over the upload tab, the tab with the arrow pointing up, left click and a drop box will appear. Images below.
3: Choose/pick/drag and drop the image you wish to upload from your picture file and left click or drag and drop the jpeg over to the box and left click on the upload tumbball image.
4: Post a brief or long description and Bob’s Your Uncle mate. …“you’re all set” or “you’ve got it made.”
Robert, are you seeing 20 amp receptacles in houses? I’m not sure if I have ever seen them used in single family dwellings.
Yes. Very Common above kitchen counters in my neck of the woods. Especially New Condo’s. At times in utilitarian rooms.
I thought maybe it was a Canadian code thing. Around here 20 amp duplex receptacles are much more expensive so no one uses them in a house. The only time you might see a 20 amp receptacle is a single receptacle.
Should have said New Homes and Condo or Updated homes.
Not a code thing. Totally Utilitarian for motors on/in appliances that require more startup current.
What drives me nuts is circuit/receptacle Vd Voltage-drop. The electrical contractor saves money using thinner AWG.
All to common in bedrooms and last few receptacles on a circuit.
The old contractor reply chestnut, Bedrooms lighting circuit on AFCI protection. My reply, what about malfunctioning appliances?
One Brand new condo unit, 80% of receptacles measured over 5% Vd. Some in the high teens or low twenties. Current as low as 95V average.
That is true Robert. I seldom encounter 20 amp duplex receptacles in homes. More prevalent in commercial/industrial applications that I inspect. However, When I remodeled my home a few years ago, I installed all 20 amp duplex receptacles with 12 AWG. They are also more robust.
I agree, they are usually all specification grade which makes them more robust and of course more expensive. 
Well, I solved the problem of the pulsating lights today. Or, I should say, a young power company service tech named Matt S. solved it. I phoned Georgia Power about 2:00 pm and asked if they would have someone check my service coming in from the street. Some trees near the street were bearing on the overhead cables, and the transformer didn’t look to healthy either. Within three hours of my phone call, Matt had cut a couple of small limbs away and had identified the real problem as squirrels gnawing on the cables, particularly the neutral. At one location on the wire, there were only two strands of the aluminum remaining. And one of the ungrounded conductors fared almost as badly, with three strands remaining under the gnawed sheathing.
That one strand (center strand) is untouched because the neutral is these triplex cables is ASCR (Aluminum Conductor Steel Reinforced) meaning that the center strand is made from galvanized steel which is not as good of a conductor compared to the aluminum. That strand and what is left of the other one that is barely intact was carrying all of the neutral current. Your original problem with the washer was symptomatic of a bad neutral. Southwire actually makes a product called SquirrelShield Triplex for area where squirrels are a problem.
I had a similar problem a few years back with squirrels doing the same thing. Glad to hear that you got it fixed bad neutrals can cause damage to the things in your home.
I think I solved it a week ago…haha 
“Most likely a loose neutral somewhere, including the possibility of the service neutral.”
Yep! Thanks, Daniel. More specifically, it was loose squirrels honing their choppers on the service cables.
Hello…I can see my lights flicker when my washer is on the agitate cycle but not the spin. How heavily was the washer loaded? I am thinking overload may cause higher amp draw and perhaps enough voltage drop to be visually noticeable. I have incandescent lights and can see this with the vanity lights in the bathroom where it’s brightest.