Elecrtical problem

[jkeyser14]

I just moved into my first house. It was built in 1954. I've got a 150 amp, 20 breaker, 2-phase main panel with a 125 amp, 2-phase sub panel in the garage (run off a 60 amp breaker in the main panel). There's 2 pole breakers for the dryer, water heater, and furnace. Then there's dedicated appliance breakers for things in the kitchen (remodeled a few years ago and up to code). The entire rest of the outlets and lights in the house are run off of the 4 remaining breakers.

Whenever the furnace or water heater cut on, the lights flicker and dim. Starting any appliance causes the voltage in the house to drop from 120v to 115v. Whenever this happens, the lights in the house noticeably dim. The same happens when I run a 7A vacuum, corded drill, etc. It's very annoying.

What's the most likely cause of this? Is it my old wiring, an undersized transformer on my street, the size of my service? Also, my main panel says it's 150 amp, but the meter outside says 200 amp on it, does this mean I might have 200 amp wiring to the meter, and possibly to the main breaker? When I bought the house the inspector commented that the wiring looked to be 200amp even though the breaker was 150 amp.

I'd like to upgrade the panel to a 40 breaker 200 amp panel, but the rest of the wiring in the basement around the panel are very obviously not to code and I'm afraid it would cause problems with the inspection.

 

[krusty the clown]

i'm not an electrician, and i didn't stay at a holiday in last night, but i had a similar problem after wiring up my shop. when the compressor came on everything dimmed and even the dusk to dawn lights reset. it was the transformer and a call to the power company fixed the problem.

 

[snyder]

It is normal in most areas for the power company to run 200 amp service to residences.
Doesn't matter what type of panel you have.. If you wanted to upgrade to a 200 amp panel, you could..
I am worried about your voltage drop problem though.. This can be caused by a bad neutral leg coming from the power pole to your house. Could be corrosion or have been damaged in a storm. If you can measure any voltage in your panel between the ground bus and the neutral bus this may be the cause.. Have it checked by a pro.. This could get dangerous..

 

[trainer]

I had the same issue in an old house I used to own. The problem persisted even after I rewired and upgraded from a 60amp service to 200 amps. Turned out the problem was with the power company. They tried to feed too many houses from the same transformer.

 

[ddawg16]

An easy way to confirm where the problem is....

Take a voltmeter and connect it to the incoming power.

Measure across one incomming line to neutral while the wife turns on a heavy load....watch the voltage swing....

Now measure the other leg to neutral....and have the wife turn on a heavy load....

If one side drops in voltage and the other goes up....it's a problem with the transformer on the pole.

 

[tfi racing]

Just call your local utility.They will come out check the connections from the pole to your meter for free and repair anything that is wrong on their side.If that doesn't solve the problem,at least you know that can be eliminated as the cause.IF you are capable and qualified,start looking for a problem with the neutral(s),and that is a big "if"-this is the kind of thing that can kill the uneducated and careless if they make a mistake!

 

[sberry]

I'd like to upgrade the panel to a 40 breaker 200 amp panel, but the rest of the wiring in the basement around the panel are very obviously not to code and I'm afraid it would cause problems with the inspection.

Normally not an issue, they assume a good start is a service upgrade and if everyone had to re-wire the whole house then they wouldn't upgrade old services, he is there to inspect the new work.
The benefit an upgrade would give is more spaces and eliminate old wire feeding the service as well as have connections replaced, as others have said, I would be looking for bad connection on the utility side or a junko transformer. My bud had an issue, called the poco a couple times, as usual, there isn't a problem,,, ha,,, until the wind blows, I checked his equipment, finally the connect gave way and dropped in the parking lot on the other side of the street. One leg drop to 90v when the wind came up, should have been obvious but got missed. Lots of these older overhead exposed connects have seen their better days and are suspect at best.

 

[sberry]

I did an upgrade a while back and left the old equipment in place untill after the inspection, the customer says "arent you going to remove it before he gets here"? I say,, no, makes it obvious why you are doing the upgrade.

 

[jkeyser14]

An easy way to confirm where the problem is....

Take a voltmeter and connect it to the incoming power.

Measure across one incomming line to neutral while the wife turns on a heavy load....watch the voltage swing....

Now measure the other leg to neutral....and have the wife turn on a heavy load....

If one side drops in voltage and the other goes up....it's a problem with the transformer on the pole.

I just got my meter and had my girlfriend turn the dryer on/off for me a few times. One of the legs drops from 122 to 119v, the other leg drops from 120v to 115v? I checked amperage on both legs and they were each pulling within .1 amps of each other. This seems to rule out a problem on my end correct?

My service entrance wire is a 2/0 aluminum wire, so if I ever do get the panel upgraded it shouldn't require a new cable run, just grounding rods?

 

[Torque1st]

I just moved into my first house. It was built in 1954. I've got a 150 amp, 20 breaker, 2-phase main panel with a 125 amp, 2-phase sub panel in the garage (run off a 60 amp breaker in the main panel). There's 2 pole breakers for the dryer, water heater, and furnace. Then there's dedicated appliance breakers for things in the kitchen (remodeled a few years ago and up to code). The entire rest of the outlets and lights in the house are run off of the 4 remaining breakers.

BTW, just as a note, you have SINGLE phase service.

A big voltage drop usually means a bad connection or a bad/overloaded device.

The dryer is a 220 device that pulls power off both legs. The water heater should do the same but it may be wired incorrectly. A bad or open Neutral connection will cause wild voltage swings when 110V appliances are switched on and off.

 

[mrb]

measure the voltage from each leg to neutral while turning on and off high draw 120v appliances such as microwave or hair dryer.

 

[jkeyser14]

measure the voltage from each leg to neutral while turning on and off high draw 120v appliances such as microwave or hair dryer.

The result is the same. I've got a drill that the nameplate says draws 7 amps and it produces the same results.

 

[jkeyser14]

BTW, just as a note, you have SINGLE phase service.

A big voltage drop usually means a bad connection or a bad/overloaded device.

The dryer is a 220 device that pulls power off both legs. The water heater should do the same but it may be wired incorrectly. A bad or open Neutral connection will cause wild voltage swings when 110V appliances are switched on and off.

The two legs are out of phase with each other which gives you the 220v, hence I called it two phase. I probably should have state two legs (although I still was right with what I said).

The neutral connection is secure in the main panel and reading voltages from any circuits on the problematic leg give similar results.

 

[Torque1st]

The two legs are the same phase, just center tapped for neutral. It is SINGLE phase power.

The result is the same. I've got a drill that the nameplate says draws 7 amps and it produces the same results.

Get the power company out. If the power company says there is no problem with their service call an electrician. Just don't tell the electrician you have two phase power, -the bill will double.