Voltage reduction?

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Raindem

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I've noticed an inssue in my workshop over the last week. It is a seperate building from the main house and has it's own sub-panel.

My heavier draw 110v tools (i.e. table saw, bench sander, shop vac, etc) are running a lot slow than normal. The table saw barely gets up to speed. The shop vac audibly slows down when the bench sander is started. GFI's trip for no reason. Nothing new has been added to the shop. FYI, the 220v circuit seems fine (my 220v compressor starts and runs OK).

Is this within the DiYer to troubleshoot or is it time to call an electrician? I have a good voltmeter but I'm not sure where to start.

Thanks

Curt
 
Seeing as how nothing changed to cause the problem and it came on fairly suddenly my guess would be you have a loose connection or ground problem. Your 220V stuff is working ok makes me think it could be on the common leg.
When you stick your meter in an outlet what does it read? What does it read when you start the sander? Try that on a circuit on each 110V leg.

That might give you some clues. Some pros should be along to offer advice soon also.
 
Aaargh. My expensive 5 year old Snap On (made-in-Korea) multi-meter broke so I'll have to use my cheap 35 year old Radio Shack (made-in-USA) multimeter, which still works and should do the trick.

Most the 110V sockets in the shop have 115V-120V going to them. For some reason one socket in the far corner has 135v. With all the sockets, if I leave the meter connected I will notice a fluctuation every few seconds, with the meter dropping 10V and then bouncing back up.

When the table saw is turned on the meter drops to 50v (at that socket) as the table saw struggles to come up to speed. When it finally gets going the meter will go back up to 115v.

When the shop vac is turned on it drops to 95v for as long as it is running.

I hooked up the portable belt sander to the same socket as the shop vac. It dropped the voltage to 105v steady, while it was running. For sake of comparison I took the belt sander over to the main house. The socket I tested had 125v going to it, and dropped to 120v while the sander was running.

The bench sander is the tool connected to the socket with 135v. When it is turned on it will drop to 125v.

Now here's the wierd thing. If I put the meter in a differnt socket (like the one the shop vac was connected to) and turn the bench sander on (which is connected to the farthest socket) the voltage on the metered socket will jump up around 10v, while the voltage at the socket that is running the tool drops by 10v.

So what does this indicate? What do I test next?

Thanks

Curt
 
Aaargh. My expensive 5 year old Snap On (made-in-Korea) multi-meter broke so I'll have to use my cheap 35 year old Radio Shack (made-in-USA) multimeter, which still works and should do the trick.

Most the 110V sockets in the shop have 115V-120V going to them. For some reason one socket in the far corner has 135v. With all the sockets, if I leave the meter connected I will notice a fluctuation every few seconds, with the meter dropping 10V and then bouncing back up.

When the table saw is turned on the meter drops to 50v (at that socket) as the table saw struggles to come up to speed. When it finally gets going the meter will go back up to 115v.

When the shop vac is turned on it drops to 95v for as long as it is running.

I hooked up the portable belt sander to the same socket as the shop vac. It dropped the voltage to 105v steady, while it was running. For sake of comparison I took the belt sander over to the main house. The socket I tested had 125v going to it, and dropped to 120v while the sander was running.

The bench sander is the tool connected to the socket with 135v. When it is turned on it will drop to 125v.

Now here's the wierd thing. If I put the meter in a differnt socket (like the one the shop vac was connected to) and turn the bench sander on (which is connected to the farthest socket) the voltage on the metered socket will jump up around 10v, while the voltage at the socket that is running the tool drops by 10v.

So what does this indicate? What do I test next?

Thanks

Curt

My experence says open neutral.
 
Do you have copper wire.
I agree you are going after white wire connections all the way back to the house. the 220 dosn't use the white.
 
If your checking voltage from hot to neutral, check it again from hot to ground and see if you still have voltage fluctuation problems. If not, then you most likely have a loose neutral. If you do, then you may have a loose hot.
 
Yes, I have copper wire. Checking my voltage from hot to ground produces the same results as hot to neutral - 10v fluctuations in the voltage.

I'm guessing I need to move to the fuse panel now. Should I check the shop sub-panel first or the main panel at the house. What should I be looking for?
 
Sounds like an open or loose neutral. Grounding rod has nothing to do with it.
 
The ground rod has nothing to do with voltage fluctuations. It also has nothing to do with voltage readings to the ground wire. The ground and neutral wires are tied together in the main panel. You could remove the rod connection and it not affect the function of the system one bit. It is there mainly for lightning protection.
 
Here's a shot of the sub-panel at the shop.

ESP.jpg


And here's a couple shots of the main panel. The 200 amp breaker on the right appears to be what's going to the shop.

EMP%201.jpg

EMP%202.jpg


So, what do I look for here? Apparently everyone says it's a loose connection but where should I focus on? I desire to poke around in there as little as possible, lol.

Thanks

Curt
 
Your checking all the screws holding the white wires on the right in the shop, the connection of the cable at the top of that and then the other end of that cable in the main
 
It could also be underground damage that you can't see.
 
So I put an allen wrench on all the connections in the sub-panel. None were loose. I put a wrench on the connections for the two thick black wires in the main panel. Neither of those were loose. I turn the power back on and it seems to be working a little better. The table saw comes up to speed withinin 15 seconds (still a little slow but better than it was) and I don't see fluctations in the volt meter.

I won't complain, but I don't understand it. Thanks for everyone's help.
 
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If you only did two wires you missed the one I think is your problem. You need to do the neutral as well.
 
Did you check the cable with the yellow stripe. That is the one bringing neutal back from the shop, I think.
 
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