Troubleshooting a customer's home

[zappy]

So most of the home's outlets were out. Old home in Berkeley. Go to the main
outside. Federal pacific. So half the panels dead. So I check the main breaker
there's 240v coming in. So I kill the main and check for continuity on the buss. Everything rings out. So I pull the main breaker off the panel, turn it on and check the stabs on it. 240v. OK so I'm thinking one of the stabs are not making a connection to the buss. I saw some oxidation on the side that's dead, where the stab goes into the buss. So I tried to clean it up. Stuck the breaker back in, and still didn't work. So is there anything I'm missing. I didn't see any damage where the main breaker stabs in, like any arcing etc. Any Idea's? Thank you for your help.

 

[Little Bill]

So most of the home's outlets were out. Old home in Berkeley. Go to the main
outside. Federal pacific. So half the panels dead. So I check the main breaker
there's 240v coming in. So I kill the main and check for continuity on the buss. Everything rings out. So I pull the main breaker off the panel, turn it on and check the stabs on it. 240v. OK so I'm thinking one of the stabs are not making a connection to the buss. I saw some oxidation on the side that's dead, where the stab goes into the buss. So I tried to clean it up. Stuck the breaker back in, and still didn't work. So is there anything I'm missing. I didn't see any damage where the main breaker stabs in, like any arcing etc. Any Idea's? Thank you for your help.

Did you check the connection/lugs where the service/feeder conductors land in the panel? Sounds like 1 leg or the neutral might be loose. Could also be at the service drop. Check the voltage with a load on it, might be a loose connection that looses continuity under load. It could also be a bad main breaker. Did you check it with a meter when you had it off?

 

[electricguy61]

It may be a split buss FPE. They were common for a while. Check for a larger 2-pole breaker that's failed (50-70amp)

I highly recommend replacing any FPE equipment.

 

[growler]

It may be a split buss FPE. They were common for a while. Check for a larger 2-pole breaker that's failed (50-70amp)

I highly recommend replacing any FPE equipment.

Split Buss sounds about right.

It was just thinking about the best way to test an FPE panel to see if it's any good and the old tried and true test for witches would work well. You take the panel and throw it in the lake and if it sinks it's good ( good boat anchor ) and if it floats is possessed by the devil.

 

[Little Bill]

Split Buss sounds about right.

It was just thinking about the best way to test an FPE panel to see if it's any good and the old tried and true test for witches would work well. You take the panel and throw it in the lake and if it sinks it's good ( good boat anchor ) and if it floats is possessed by the devil.

Witches

I forgot about the split bus, good point!

 

[cowboyjwc]

You said you had 220 volts, but did you have 110 L-N?

When you drop a leg I can never remember if you get 220 but not 110-110 or you get 110-110 but not 220. Don't do that much service work any more. Of the three times I've found it, it's only been the breaker once and it was POCO the other two times.

 

[growler]

You said you had 220 volts, but did you have 110 L-N?

When you drop a leg I can never remember if you get 220 but not 110-110 or you get 110-110 but not 220. Don't do that much service work any more. Of the three times I've found it, it's only been the breaker once and it was POCO the other two times.

When you drop a leg you can still read 110-120 on each of the legs. There can be feed back through one of the 240 V circuits. The one going to the water heater/AC unit is normal. If you flip off all the double pole breakers then there is no path for feed back and you will see which leg is missing.

 

[cowboyjwc]

When you drop a leg you can still read 110-120 on each of the legs. There can be feed back through one of the 240 V circuits. The one going to the water heater/AC unit is normal. If you flip off all the double pole breakers then there is no path for feed back and you will see which leg is missing.

OK, so you get 110 L-N but not 220 L-L. I know what it is when I see it, but like I said I just hardly ever put on my tools anymore.

 

[zappy]

Did you check the connection/lugs where the service/feeder conductors land in the panel? Sounds like 1 leg or the neutral might be loose. Could also be at the service drop. Check the voltage with a load on it, might be a loose connection that looses continuity under load. It could also be a bad main breaker. Did you check it with a meter when you had it off?

Service enterance conductors land right into the 100amp breaker. I left those wires attached to it, pulled the breaker off the panel, turned it on and checked the stabs. I was getting 240v through the breaker. So how could the breaker be bad? When I plugged it back into the panel, only half the panel is live. I checked 120v to ground on each leg of the buss, and only one side is working.

 

[zappy]

You said you had 220 volts, but did you have 110 L-N?

When you drop a leg I can never remember if you get 220 but not 110-110 or you get 110-110 but not 220. Don't do that much service work any more. Of the three times I've found it, it's only been the breaker once and it was POCO the other two times.

Yes checked voltage to ground on both sides of the buss. One side is dead.

 

[mtfallsmikey]

Excellent sales opportunity for a new panel!

 

[growler]

Service enterance conductors land right into the 100amp breaker. I left those wires attached to it, pulled the breaker off the panel, turned it on and checked the stabs. I was getting 240v through the breaker. So how could the breaker be bad? When I plugged it back into the panel, only half the panel is live. I checked 120v to ground on each leg of the buss, and only one side is working.

Is it possible that the buss is burned into where you can't see it? Check continuity from the place where you plug in the main to were the breakers stab lock.

All you really need to know is that you have power at point "A" and don't have it at point "B" to know there is a problem somewhere between the two points.

Almost any thing you can do to a Federal Pacific panel will cost more and do less good than replacing that hunk of junk.

 

[fireryan]

When you drop a leg you can still read 110-120 on each of the legs. There can be feed back through one of the 240 V circuits. The one going to the water heater/AC unit is normal. If you flip off all the double pole breakers then there is no path for feed back and you will see which leg is missing.

Can you explain to me how you would get a backfed from a 240v water heater or a AC

 

[cowboyjwc]

You need to check the line side of the meter socket, to make sure that it's not on the utility side.

 

[growler]

Can you explain to me how you would get a backfed from a 240v water heater or a AC

I'm surprised you haven't noticed this. I have had three incidents in about the last two months where one leg was dropped and they were still reading 120 on each leg but not 240 from phase to phase. It really doesn't matter where the leg is lost it can be underground, a bad meter lug or one side of a main breaker.

The idea is that there is one 120 volt phase comming in and the other phase is open somewhere. You would think that maybe half the circuits would be dead but they are not or at least not all the time. The one leg that's still live feeds through the heating element of say a water heater and make the othe side of the two pole breaker protecting the water heater live and thus back feeds that side other bus also. You can check all the breakers to neutral and still read 120V and even the lights will still work as long as power is feeding through something. Turn off all the double pole breakers and there is no return path and half the panel will go dead.

We learned this in school 35 years ago so it's just basic stuff. Makes a nice little test question to get people to think. :dunce:

 

[zappy]

Is it possible that the buss is burned into where you can't see it? Check continuity from the place where you plug in the main to were the breakers stab lock.

All you really need to know is that you have power at point "A" and don't have it at point "B" to know there is a problem somewhere between the two points.

Almost any thing you can do to a Federal Pacific panel will cost more and do less good than replacing that hunk of junk.

I did check for continuity. And it was fine. That's why I think it's a bad connection between the main breaker and the buss.

 

[zappy]

You need to check the line side of the meter socket, to make sure that it's not on the utility side.

Well if I have 240v coming out of the meter, why would I need to check the line side?

 

[zappy]

Excellent sales opportunity for a new panel!

YES. I said they need a new panel. And I gave them a price. Those hippies, there so cheap, I mean frugal.

 

[readydave8]

Can you explain to me how you would get a backfed from a 240v water heater or a AC

your resistance becomes a conductor (probably not an accurate statement but makes it easier to understand).

 

[readydave8]

Service enterance conductors land right into the 100amp breaker. I left those wires attached to it, pulled the breaker off the panel, turned it on and checked the stabs. I was getting 240v through the breaker. So how could the breaker be bad? When I plugged it back into the panel, only half the panel is live. I checked 120v to ground on each leg of the buss, and only one side is working.

If you have 240v with breaker pulled off panel but not when it's plugged in--is it possible that you only see 240v on your meter until you put a load on breaker? Maybe you thought of that and tried it installed in panel with all other breakers off.