Any electricians on here?

[charly]

1840 Farmhouse, 200 amp service.. What they did do is leave a knife switch ahead of the main panel with two 100 amp fuses, plus the breaker box has it's own 200 main breaker.. Since we bought the place , I always noticed if you run a saw, or the vacuum, you can see the lights do a slight but noticeable quick dim.. Well for the heck of it I plugged a digital volt meter into an outlet in the kitchen.. Now I watched,, had 119 volts, had the wife turn the vacuum on , it dropped and stayed at 116 volts while it's running... She was plugged in upstairs on a different circuit.. If I open our refrigerator door I can watch the meter drop a half of volt as the light comes on... Do I have corrosion on a meter leg or a bad neutral or main ground issue some wheres? How about those old fuses? I checked every wire except the mains in my box, all tight.. Couldn't wiggle the mains.. Shouldn't the voltage stay the same as things are powered up? I'm wondering if this is causing us to use more power then needed, thus giving us a higher bill then we should be seeing.. Try to figure where to start.. Another person said we could be at the end of a primary run, thus needing transformer on the pole...I'm all open for what might be the issue here. Be nice to find out we have an issue and can get our power usage down...I always thought our KWH usage was higher then it should be for what's running here..

 

[begreen]

Not sure why the knife switch was left, particularly with lower amperage fuses. I'd eliminate it for starters. Many things can influence voltage drop. As you have noted, corroded meter jaws, and oxidizing connection (esp. if aluminum), bus corrosion, undersized wire, etc.. In our house we had a serious voltage drop that turned out to be the neutral leg from the pole was failing. It was rubbing up against maple tree and slowly failing.

 

[Jack Straw]

They probably left the knife switch so they could cut the power to install the breaker box. The 2-100 amp breakers equal the 200 amp breaker box. The old famers were very cheap!

 

[begreen]

It's easy to just to pull the meter if you want to cut the power. The knife switch add 4 connection points and the knife contacts which are all potential loss points and the switch presents a potentially lethal shock hazard.

 

[seige101]

Can you post a few pics for us? One of the outside wire going into the meter and then the wires going in and out of the knife switch.

Sounds like they only upgraded half your service

 

[Highbeam]

They probably left the knife switch so they could cut the power to install the breaker box. The 2-100 amp breakers equal the 200 amp breaker box. The old famers were very cheap!

Not true, the 100 amp breakers are one per leg so you are only breakered at 100 amps to feed a 200 amp panel. Remember this is 240 so each hot line must have have a 200 amp CB.

Another thing to consider is that the entire service between the panel and the transformer may be sized for 100 amps. Removing that 100 amp knife switch means you are doubling the potential current in the line. Time to get the whole thing checked out, you may be limited to 100 amps.

 

[Jack Straw]

Oh your right! I never realized that.

 

[charly]

I'll get some pics together.

 

[charly]

says 240 vac on the tag


I notice the braided ground go no wheres on the lower left in the box... Maybe an issue coming from the neutral.

 

[begreen]

Hare to tell but it looks like they kept the original 100 amp feed from the strike and meter. What is the gauge of the neutral going to the breaker panel?

 

[ewdudley]

Not true, the 100 amp breakers are one per leg so you are only breakered at 100 amps to feed a 200 amp panel. Remember this is 240 so each hot line must have have a 200 amp CB.

Another thing to consider is that the entire service between the panel and the transformer may be sized for 100 amps. Removing that 100 amp knife switch means you are doubling the potential current in the line. Time to get the whole thing checked out, you may be limited to 100 amps.

What HB said. If the service wiring is only good for 100 amperes then need to leave well enough alone. The fuses and knife switch look just fine from the pictures.

You can investigate the voltage drop further by connecting your meter to the mains or other unrelated circuits to see if the whole house leg is dropping as opposed to just the circuit that the vacuum is connected to.

 

[charly]

Hare to tell but it looks like they kept the original 100 amp feed from the strike and meter. What is the gauge of the neutral going to the breaker panel?

2/0 I'm thinking my triplex from the pole might be undersized? Maybe for 100 amp.. Was all done before we bought the place... I was shocked to see a 200 amp box filled for the 1900 sq ft.. They must have really broke the circuits down, which I guess is a good thing.. Just don't like seeing that voltage drop thing going on and staying there.. I think that's odd.. Have to look inside the meter box,,, maybe major corrosion on one leg or a neutral. Something is pulling current because of the lights dimming when a load comes on..

 

[ewdudley]

Also: " had 119 volts, had the wife turn the vacuum on , it dropped and stayed at 116 volts while it's running.."

If circuit is 150 ft round trip 12 gauge copper, and vacuum draws 15 amperes, then 15 amperes times 150 ft times 1.588 ohm per 1000 ft equals 3.573 volts. Dropping from 119 to 116 VAC would be a small surprise.

 

[charly]

Also: " had 119 volts, had the wife turn the vacuum on , it dropped and stayed at 116 volts while it's running.."

If circuit is 150 ft round trip 12 gauge copper, and vacuum draws 15 amperes, then 15 amperes times 150 ft times 1.588 ohm per 1000 ft equals 3.573 volts. Dropping from 119 to 116 VAC would be a small surprise.

So that is a normal voltage drop? Thing is the vacuum was on another circuit. Even when running a circular saw plugged into an outdoor receptacle , the kitchen lights still do that quick dim thing... That's what I'm trying to figure out..

 

[ewdudley]

So that is a normal voltage drop? Thing is the vacuum was on another circuit. Even when running a circular saw plugged into an outdoor receptacle , the kitchen lights still do that quick dim thing... That's what I'm trying to figure out..

Inrush amperage on the circular saw maybe 4X rated amperage, call it 60 amperes, with long extension cord even worse. Certainly enough draw to cause a voltage dip for the whole house that you could see in all the light bulbs.

 

[jharkin]

[Not an electrician]

First off I concur with everybody else - You have a 200 amp panel but they left the 100 amp service. Looking at the photos the wires looked a bit small. You say that the wires from the disconnect to the panel are 2/0 - looks like copper 2/0. Its hard to see but the service entrance wires on the other side of hte fuse look like similar sized aluminum? If you do indeed have 2/0 Aluminum service entrance than you definitely still have e old 100amp service entrance setup - When I had 200amp service put in they wired me with 4/0 Aluminum to the weatherhead.

So my guess? Somebody ran out of panel space for more circuits and decided to cheap out on an all new service and just put in the 200 box for the breaker space. In this case the 200amp main is only acting as a box disconnect and not providing main overcurrent protection.


Now, all of this doesn't explain your voltage drop around the whole house. Ewdudley's calculations sound right (other than I dont think I've ever seen a vacuum over 12A) but you would only see that behavior at the far end of the circuit with the load on it. You seem to see it on all circuits when any one circuit is loaded and that tells me the problem is upstream. First I would confirm that by randomly trying loads on a few different circuits and testing other circuits - ideally test an outlet as close to the panel as possible.

Once confirmed that this is really effecting the entire house its time to check everything upstream - look at the blade fuse disconnect. Check that they properly connected those aluminum wires (aluminum rated connectors, clean wire, coated connections with anti-oxidant grease). You might want to hire a pro to look at this and to check the connections up at the weatherhead. If all that checks out (and it might well) it could be a problem on the utility side - maybe a transformer going bad or something (this is beyond me).


[/Not an Electrician]

 

[charly]

[Not an electrician]

First off I concur with everybody else - You have a 200 amp panel but they left the 100 amp service. Looking at the photos the wires looked a bit small. You say that the wires from the disconnect to the panel are 2/0 - looks like copper 2/0. Its hard to see but the service entrance wires on the other side of hte fuse look like similar sized aluminum? If you do indeed have 2/0 Aluminum service entrance than you definitely still have e old 100amp service entrance setup - When I had 200amp service put in they wired me with 4/0 Aluminum to the weatherhead.

So my guess? Somebody ran out of panel space for more circuits and decided to cheap out on an all new service and just put in the 200 box for the breaker space. In this case the 200amp main is only acting as a box disconnect and not providing main overcurrent protection.


Now, all of this doesn't explain your voltage drop around the whole house. Ewdudley's calculations sound right (other than I dont think I've ever seen a vacuum over 12A) but you would only see that behavior at the far end of the circuit with the load on it. You seem to see it on all circuits when any one circuit is loaded and that tells me the problem is upstream. First I would confirm that by randomly trying loads on a few different circuits and testing other circuits - ideally test an outlet as close to the panel as possible.

Once confirmed that this is really effecting the entire house its time to check everything upstream - look at the blade fuse disconnect. Check that they properly connected those aluminum wires (aluminum rated connectors, clean wire, coated connections with anti-oxidant grease). You might want to hire a pro to look at this and to check the connections up at the weatherhead. If all that checks out (and it might well) it could be a problem on the utility side - maybe a transformer going bad or something (this is beyond me).


[/Not an Electrician]

Definitely going to have it looked at... I want to see what the home inspection guy missed!

 

[charly]

[Not an electrician]

First off I concur with everybody else - You have a 200 amp panel but they left the 100 amp service. Looking at the photos the wires looked a bit small. You say that the wires from the disconnect to the panel are 2/0 - looks like copper 2/0. Its hard to see but the service entrance wires on the other side of hte fuse look like similar sized aluminum? If you do indeed have 2/0 Aluminum service entrance than you definitely still have e old 100amp service entrance setup - When I had 200amp service put in they wired me with 4/0 Aluminum to the weatherhead.

So my guess? Somebody ran out of panel space for more circuits and decided to cheap out on an all new service and just put in the 200 box for the breaker space. In this case the 200amp main is only acting as a box disconnect and not providing main overcurrent protection.


Now, all of this doesn't explain your voltage drop around the whole house. Ewdudley's calculations sound right (other than I dont think I've ever seen a vacuum over 12A) but you would only see that behavior at the far end of the circuit with the load on it. You seem to see it on all circuits when any one circuit is loaded and that tells me the problem is upstream. First I would confirm that by randomly trying loads on a few different circuits and testing other circuits - ideally test an outlet as close to the panel as possible.

Once confirmed that this is really effecting the entire house its time to check everything upstream - look at the blade fuse disconnect. Check that they properly connected those aluminum wires (aluminum rated connectors, clean wire, coated connections with anti-oxidant grease). You might want to hire a pro to look at this and to check the connections up at the weatherhead. If all that checks out (and it might well) it could be a problem on the utility side - maybe a transformer going bad or something (this is beyond me).


[/Not an Electrician]

The hots from the fuse box are copper that go to the main breaker panel.. They are of the proper size, twice as big as the 2/0 aluminum neutral . Can't see any wire gauge size on the copper..The fuse box is labeled 200 amps, so 100 amps on each leg coming in.. It's aluminum wire coming into the fuse box from the meter.. I'm betting there is an issue in the meter box.. Think I will ditch the aluminum from the pecker head in and by pass the fuse box, going directly to the 200 amp service panel.. I'll also confirm the wire size coming in from the pole... That's a good 100 ft plus run as well... Maybe that service entrance wire should be sized bigger for the run as well.. I know a few local electricians who will check things out for me...

 

[jharkin]

Highbeam was right up thread... 200 amp service means a 200 amp breaker on each leg. Since you have a 100 amp fuse on each leg you effectively have 100 amp service regardless of what the panel sticker says.

 

[charly]

Highbeam was right up thread... 200 amp service means a 200 amp breaker on each leg. Since you have a 100 amp fuse on each leg you effectively have 100 amp service regardless of what the panel sticker says.

I thought 100 amps on each side gave you 200 total Plus the breaker box has a 200 amp main breaker. I really have to get this looked at and find out what's what... I know I want to get rid of those fuses...

 

[jharkin]

The 200 breaker in the main box is a double pole breaker - I.e. 200 on each leg.

A 200 amp residential service gives you 200A at 240v ( hot to hot) for 48kW of available power. Wire up enough 120 volt loads and in theory you could draw 400A at 120v (hot to neutral) if you max both hot legs.

Needless to say most of us don't come anywhere close to maxing one out, even all electric households.

 

[charly]

Just took a closer look, each fuse does say 200 amps, my mistake... I'm thinking in the meter can there are some issues with the aluminum service wire...corrosion or loose connection.. Plus the wires coming out of the weather head look pretty sun beat...insulation is showing wear..

 

[oldspark]

Doesn't sound like much of a voltage drop to me, electricity is not magic.

 

[fbelec]

from what i see you have a 200 amp service. the wires coming in 2/0 copper is 200 amp. the wire coming from the meter to the fuse disconnect look like aluminum but are copper. when those wires were put in they didn't use aluminum wire i don't think that aluminum was on the market at that point. those wires are what is called copper clad. which is copper with a small coat of i think lead to keep the copper from corroding. water could get into those old wires so they did not want in to turn green. you need to do the same test with your vac or saw but take the volt reading at the line side of your meter. also check the other phase to see if there is a voltage drop or rise if you get a voltage rise you could be having issues with the neutral and are using the ground as neutral which would be a #4 copper. if you have 116 volts under load the power company prob won't listen. but if you turn on a few heavy draws in the house and you are dropping to 110 or lower they come out to see. those old crimp connectors that are outside up at the weatherhead are always a problem. and or at the pole. i run into that old wiring all the time here in mass. lots of old houses up here. btw up here the only time i see the power company up size their wire is when the old stuff failed due to the current load. i have had the power company a number of times hook up my 500 mcm copper (400 amp) wire to their 1/0 aluminum service drop and when questioned they told me it was fine and would replace it if it failed. single phase like houses and commercial power 3 phase.NICE.

frank

 

[charly]

from what i see you have a 200 amp service. the wires coming in 2/0 copper is 200 amp. the wire coming from the meter to the fuse disconnect look like aluminum but are copper. when those wires were put in they didn't use aluminum wire i don't think that aluminum was on the market at that point. those wires are what is called copper clad. which is copper with a small coat of i think lead to keep the copper from corroding. water could get into those old wires so they did not want in to turn green. you need to do the same test with your vac or saw but take the volt reading at the line side of your meter. also check the other phase to see if there is a voltage drop or rise if you get a voltage rise you could be having issues with the neutral and are using the ground as neutral which would be a #4 copper. if you have 116 volts under load the power company prob won't listen. but if you turn on a few heavy draws in the house and you are dropping to 110 or lower they come out to see. those old crimp connectors that are outside up at the weatherhead are always a problem. and or at the pole. i run into that old wiring all the time here in mass. lots of old houses up here. btw up here the only time i see the power company up size their wire is when the old stuff failed due to the current load. i have had the power company a number of times hook up my 500 mcm copper (400 amp) wire to their 1/0 aluminum service drop and when questioned they told me it was fine and would replace it if it failed. single phase like houses and commercial power 3 phase.NICE.

frank

Thanks for the info Frank... I'm going to get a hold of someone to check those weather head connections... Wire up there is getting pretty beat looking so maybe run a new wire into the meter can and see what the connections look like in there as well.. I have a friend that works for the local power company,, she was a lineman at one point... I'm sure she can get someone out here if it comes down to that...Just don't want to leave things they way they are, with the lights dimming.. I think there's a solution for that...and maybe be better for my power bill as well.
Charlie