200 amp Panel Help, Please


  #1  
Old 09-29-05, 07:55 AM
tjm0852
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200 amp Panel Help, Please

Newbie to this forum, I would appreciate any help.
Here the deal: I am putting new circuits in at a friends house he has a 200 Amp Murray panel with lots of free space to add breakers.
Here is the problem thought. He already has a 50 amp sub-panel, 50 amp for one range, 50 amps for another range, 30 amps for a dryer, roughly 6 20 amp breaker and well over 8- 15 amp breaker. I am trying to add another 30 amps for a second dryer. Every time I throw the breaker 30 amps the breaker blows and you can see it arching to the back of the panel. I thought the breaker was bad or I had too much conductor exposed. I tried another breaker and the same thing happened. When you look at the buzz bar you can see where it actually burnt some. Everything is grounded properly.
Am I overloading the panel? That's what I am guessing.
What can I do? Install a sub-panel? Wouldn't the total overall amperage still be the same or would that fix the problem.
TIA for any advice.
 
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Old 09-29-05, 08:06 AM
J
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I am putting new circuits in at a friends house
Correction: He's putting in the new circuits (with a permit of course), and you're assisting.

Am I overloading the panel?
Is it the 30-amp breaker that's blowing, or the 200-amp breaker? Chances are that you're not overloading the panel, but merely that you wired a short circuit into the new circuit. Don't keep throwing that breaker or pretty soon your ex-friend will be spending $2000 on a panel replacement.
 
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Old 09-29-05, 08:06 AM
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Not the expert, but here are my thoughts.
Even if the panel was overloaded, it would be the main tripping not the 30 dryer breaker.
have you checked the wire for a short?
If you bought that orange 10 gauge crap wire the sell at the big box store, it is very possible the wire is damaged in the wire clamp either at the breaker or the outlet.
It happened to me....
You have to treat that stuff like it glass...just snug the clamp...do not overtighten...it will short every time.
 
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Old 09-29-05, 08:16 AM
tjm0852
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Originally Posted by John Nelson
Correction: He's putting in the new circuits (with a permit of course), and you're assisting.
Yes, exactly. And it is the 30 amp breaker not the 200 amp one.

Originally Posted by Stevetra
have you checked the wire for a short?
If you bought that orange 10 gauge crap wire the sell at the big box store, it is very possible the wire is damaged in the wire clamp either at the breaker or the outlet.
It happened to me....
You have to treat that stuff like it glass...just snug the clamp...do not overtighten...it will short every time.
Another question is, have a fried those breakers or are they still ok to use?
Should I just suck it up and get a new one?

I will double check for a short but unforunately the walls have been since closed up. Hopefully the short is not in the wall. It is the orange wire from HD, I didn't realize it was so fragile. I will double check at the outlet box, because I did tighten the crap out of that clamp. Glad I have a loop of extra cable.
Thanks for the tips. I'll let you know how it goes.
 
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Old 09-29-05, 09:06 AM
J
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Your breakers should still be okay.

Good luck finding the short.
 
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Old 09-29-05, 12:01 PM
tjm0852
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I am going to install the breaker with no wires on it and make sure that the breaker is good and the buzz bar position is OK. I am guessing one of my power leads is grounded. My buddy (used to be an electrician) said to use a test lamp from one pole of the breaker to one of the hot leads to the plug. If the light lites up then that cable is grounded somewhere.
Does that sound like a good way to test for a short?
 
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Old 09-29-05, 12:18 PM
R
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Actually, if you have the panel open, just test between the terminal on the breaker and the hot disconnected hot wire. The try the other disconnected hot wire.
 
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Old 09-29-05, 01:47 PM
M
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Originally Posted by Stevetra
If you bought that orange 10 gauge crap wire the sell at the big box store, it is very possible the wire is damaged in the wire clamp either at the breaker or the outlet.
It happened to me....
You have to treat that stuff like it glass...just snug the clamp...do not overtighten...it will short every time.
Are you referring to NM cable in general, or just the stuff from the big stores? 'Cause around here it's the same brand and the same packaging at what you get at the electrical wholesalers, too.

But, yes, you do have to exercise reasonable care in landing it; good point.
 
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Old 09-30-05, 05:50 AM
tjm0852
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Originally Posted by Stevetra
have you checked the wire for a short?
If you bought that orange 10 gauge crap wire the sell at the big box store, it is very possible the wire is damaged in the wire clamp either at the breaker or the outlet.
It happened to me....
You have to treat that stuff like it glass...just snug the clamp...do not overtighten...it will short every time.
^^SPOT ON^^
The black power lead was shorting out on the clamp at the outlet box. Good thing I left extra cable so I could cut back the shorted part of the cable and re-terminate it.
THANKS!!!
 
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Old 10-01-05, 10:47 AM
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Figured that would be the case. If the issue was with the panel itself you would have had a main breaker tripping. In your case it was the 30A which indicated a dead short somewhere and in all cases like this go to the end device and check it....if possible pull it loose and wirenut the conductors for protection and then re-insert the breaker and see if it holds....if it does the problem has to be in the device or appliance.
 
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Old 10-02-05, 01:36 PM
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Separate issue that you should check:

In your initial post, you said 'Every time I throw the breaker 30 amps the breaker blows and you can see it arching to the back of the panel. I thought the breaker was bad or I had too much conductor exposed. I tried another breaker and the same thing happened. When you look at the buzz bar you can see where it actually burnt some.'

This says to me that in addition to the short circuit problem that caused the breaker to trip, there is another problem with the fit of the breaker on the 'bus' bar. Arcing and burn marks on the bus bar are a sign of a bad connection to the breaker. The burn marks can themselves result in a worse connection to the breaker, which will cause heating every time that circuit is used, and a vicious cycle eventually leading to significant damage to the bus. At this point you have to replace the service panel; not a cheap job.

Were you using breakers specifically made for this panel? Or breakers that seem to be the right size and seem to fit? Have you confirmed that the breaker is properly seated? Did you investigate the extent of the visible arc damage?

-Jon
 
 

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