EPAIII
Diamond
- Joined
- Nov 23, 2003
- Location
- Beaumont, TX, USA
Yes, yes, YES! The air compressor circuit itself is not where your problem is. If the 30 Amp breaker is not tripping and the existing wire (in wall and any cord) is not getting hot, then replacing them is not going to stop the lights from dimming unless the lights are on that same 30 Amp breaker. Which I highly doubt.
The problem has to be BEFORE the sub panel where the 30 Amp breaker is.
Do look at the house lights first. If they do not dim, then all is OK up to the main panel in the house.
As a first and simple thing to do you can turn the breaker in the main panel that feeds the shop panel. Then tighten up the connections from that breaker to the line to the shop panel. Also, while the power is off, tighten the connections where that line enters the shop sub panel. You could tighten the other connections in that sub panel at the same time.
If the problem still exists after that, check the line from the main panel to the sub panel for damage or splices. Repair any problems that may show.
If all that fails, call a good electrician.
PS: LED and CFL bulbs can have unknown characteristics, like slow turn off times. Good old incandescent bulbs, which have no electronics in them, are best for the checks.
The problem has to be BEFORE the sub panel where the 30 Amp breaker is.
Do look at the house lights first. If they do not dim, then all is OK up to the main panel in the house.
As a first and simple thing to do you can turn the breaker in the main panel that feeds the shop panel. Then tighten up the connections from that breaker to the line to the shop panel. Also, while the power is off, tighten the connections where that line enters the shop sub panel. You could tighten the other connections in that sub panel at the same time.
If the problem still exists after that, check the line from the main panel to the sub panel for damage or splices. Repair any problems that may show.
If all that fails, call a good electrician.
PS: LED and CFL bulbs can have unknown characteristics, like slow turn off times. Good old incandescent bulbs, which have no electronics in them, are best for the checks.
You have a voltage drop.
Simple ohms law.
Current through a resistance causes a drop in voltage across the resistance.
Digital voltmeter is too slow.
Your lights however, AR working fine for this.
Do lights dim in house?
No?
Lights on sub panel dim so voltage drop between main panel and shop panel.
If yes, then drop between supply and main panel.
Often the main breaker can get oxidized where it connects to buss.
Depending on your panel, you may have access to the wire on the meter side of main breaker.
Carefully attach a test light to this connection and ground other side.
When you fid the spot that does not dim as much then inspect it.
You can use your light, one side to each side of breaker, any light indicates problem.
We have 7.5 hp single phase with proper unloader, lights indicate compressor starting but just tiny amount.
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