Help with dimming lights in house.

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papakevin

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So, I’m at a bit of a loss on this one.
My son is moving into my parents old house at the end of the month. The house originally had an old screw in fuse system, so upgraded to a 100amp breaker box and had a certified electrician upgrade the feed cable from the meter to the main breaker. He also installed a new dedicated ground wire and rod.
When I have a shop vac connected to a newly installed circuit and turn it on, it will dim the lights in the house, which are on an old separate existing circuit. What could be causing this issue? Is it something to worry about? Photos of the panel before / after attached for reference.
 

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bud16415

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Is it only with the shop vac or will another large item plugged in cause a dimming. Something like a skill saw? Is it only the one outlet that has the problem or anyplace you plug the vac in will cause it?

When you say the lighting is on an old circuit, does that mean it is the original wire but now running to the new panel? Or something else?
 

papakevin

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It will dim with a skill saw hooked as well. I’m connecting it to the new circuit plug directly under the panel, you can see it in the photo. I believe it happens with any plug in the home, but will confirm that later today.
The wiring for the ceiling lights is original to the house, so probably from the late 40’s.
 

Eddie_T

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Is the dimming momentary or all the time the vacuum is on? With the location of the receptacle the older wiring would not be involved. You might check a receptacle that's close but on the other leg of the panel.
 

afjes_2016

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I am a bit confused. You show the original fuse box. Three conductors feeding it. Two hots and a neutral. Then you show the replacement being a breaker panel with 4 conductor SER - two hots, neutral and a ground. Also the breaker panel is bonded (green screw). If 4 conductors are feeding it this is probably a sub panel. Is there a disconnect prior to this panel? If so then this panel is not wired correctly. If there is a main disconnect prior to this panel then the grounds and neutrals should be isolated. I cant enlarge it enough to see if there are any grounds on the neutral bars and if there is a ground bar hidden behind all those wires.

Someone with better eye sight please look at it and let me know if you agree.
 

papakevin

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1634207718244.jpeg
Hopefully this photo will show up better. The original (old) feeder wire from the meter was too small for a 100 amp panel, so the electricians had to run a new supply line directly from the meter to the new panel. I asked them to install a new grounding rod outside, so they did. I’m assuming the 4th wire you reference is the ground wire, which is attached to the grounding bar.
Looking at this photo, does everything look ok? My son is moving into the house at the end of this month, so want to make sure it is safe. Thanks.
 

afjes_2016

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This four conductor wire. Can you please read what it says on the outside sheathing of the cable. It should be printed with something like a number and AWG. I'd like to know what the wire gauge is that is why I am asking. I can't see clearly but is the main breaker at the top of this panel 100amp?

Are you saying they placed the ground rod at the meter can and that is why now there is a 4 conductor feed to this panel? It is still a bit confusing because they bonded this panel with the screw but you say there is no disconnect prior to this panel so it should be considered the main panel which would require bonding of the neutral and ground.
 

Jeff Handy

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Your parents’ house probably had 60 amp fused service.
Just adding a new wire from the meter and a 100 amp panel is not going to magically increase the amperage from the utility.
You have to pay them to upgrade your service to 100 amp, and usually that also requires a new heavier wire from the pole over to your meter.
Sometimes the original utility service wire was oversized, planning ahead for the amperage upgrade in the future.
 

bud16415

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Here is a video you can watch where he explains the need for bonding ground and neutral in the main panel as afjes is explaining. It looks like there is nothing attached to the green screw at the top of your main panel. I'm not sure if this is the cause of your dimming but should be corrected if the panel is the main as you say.
 

bud16415

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To Jeff’s point on the size of your service. Whenever I have asked around here the power company always said they sized the conductors large enough in the day of 60a services to handle 100a today. That could be different in other areas I don’t know. When people jump to 200a services is when I see new feeders brought in from the pole.
 

Eddie_T

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It looks correct to me. The panel is the first disconnect, the feed is 3 conductor + ground and the panel is bonded.

The video above has some errors in it but is essentially OK.
 
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afjes_2016

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It looks correct to me. The panel is the first disconnect, the feed is 3 conductor + ground and the panel is bonded.

The video above has some errors in it but is essentially OK.
Usually the first disconnect or panel after the meter is considered the main. There the ground and neutral is bonded. Three conductor plus ground in this case is showing that it is wired as a sub panel in which case the green ground screw should not be installed in the panel. If this is in fact the the main panel (and this is the first panel or disconnect from the meter and meter has no breaker or disconnect within it) then this is now considered the main panel. Seems very odd that if this is the main panel that there are four conductors going to it. Usually it would be three conductors from the meter to the main panel - two hots and a neutral and then if ground rods used the ground rods would be install and connected to the main panel. The ground screw would be present in this case. Again, seems odd that 4 wires come into this panel if this is "considered the main panel".

Bud, the green ground screw is only used in the main panel.
You say "It looks like there is nothing attached to the green screw at the top of your main panel. " There would not be anything attached to the green ground screw. The ground screw is nothing but a machine screw that goes into the hole that makes contact with the neutral bar and metal panel thus bonding it. You would not see any wire connected to the green ground screw. Maybe I am not understanding what you are saying.
 

Eddie_T

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I call it 3 conductor + ground and assume that the ground connects to the ground rod the OP had installed presumably near the meter tray. I think we are moving away from the OP's concern regarding dimming lights.
 

Eddie_T

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We are doing a lot of guessing. Wouldn't the electrician have to pull the meter to upgrade the feed? If so would the utility reinstall the meter w/o proper wiring in and out of the tray? If the electrician reinstalled the meter it will have a broken seal.The meter should have amps listed on its ID plate.
 

afjes_2016

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The house originally had an old screw in fuse system, so upgraded to a 100amp breaker box and had a certified electrician upgrade the feed cable from the meter to the main breaker. He also installed a new dedicated ground wire and rod.
EddieT - Us discussing the new feed to the main panel is part of the OPs original post #1. If there are issues with it we should make them clear to the OP.
 

papakevin

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Hey guys, really appreciate the feedback and the video link. After watching the video, I realized I didn’t know as much about electricity as I thought.
I’m attaching photos of the meter and the wires coming into the meter itself. The meter was replaced within the last 15 years because it is now a smart meter. The wires from the utility appear to be the right size / large enough to support a 100amp service, but it’s hard for me to tell.
The electricians did pull the meter and run a new line in the crawl space from the meter to the main (and only) box inside, which is why it is feeding up from the bottom of the panel.
 

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Eddie_T

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That's the same meter I have, 200A-240V. It looks like everything's in order. The utility may even have you wired for 200A service up to the meter tray. I can see the printing on the cable sheath coming into your breaker panel but can't read it when I zoom on it.
 
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