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Old 04-01-2013, 04:37 PM   #1
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I have a 30 year old house with a GE electrical box I need to replace the breaker for the range but my box doesn't seem to have a main breaker! can I still work on the breaker to be replaced safely?

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Old 04-01-2013, 04:43 PM   #2
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Could you post a picture of the panel?

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Old 04-01-2013, 05:54 PM   #3
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30 years ago, "split-bus" panels were all the rage. Dirt cheap, since no "main" breaker was needed.

There were several 2-pole breakers in one section of the panel, one or 2 of those sub-fed the other sections of the panel for "lighting" loads.

As long as there were 6 or less breakers in the main section, it was Code-compliant.

If the range breaker is in that section, there is no way to switch off the bus without involving the power company.

Unless you have an outside disconnect box.
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Old 04-01-2013, 06:53 PM   #4
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I don't know your skill level but it is common practice for electricians to work in a panel and change a breaker with turning off the main breaker. You have to be aware of what not to touch.
If you have a split bus panel then you do not have a choice unless you call the POCO for a disconnection from the line.
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Old 04-01-2013, 07:51 PM   #5
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Working inside a live panel box is VERY DANGEROUS. Those who do it for a living understand the risks, and typically wear protective equipment, including face shield, insulated gloves, and arc fault protection clothing. I have had occasion to review cases involving horrendous injury and several fatalities involving experienced electricians who inadvertently worked on a live panel they thought was dead. These were experienced individuals who made errors in procedure and judgement. Any recommendation that an untrained individual work on a live panel is, in my opinion, unnecessarily dangerous and an incredibly bad idea. If you cannot shut the panel off, you need an electrician to do this work.
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Old 04-01-2013, 08:31 PM   #6
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I think we need a picture and/or some more information. We don't know whether or not its a split bus panel or just a sub panel coming from an outside disconnect.
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Old 04-02-2013, 07:55 AM   #7
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Quote:
Originally Posted by Daniel Holzman View Post
Working inside a live panel box is VERY DANGEROUS. Those who do it for a living understand the risks, and typically wear protective equipment, including face shield, insulated gloves, and arc fault protection clothing. I have had occasion to review cases involving horrendous injury and several fatalities involving experienced electricians who inadvertently worked on a live panel they thought was dead. These were experienced individuals who made errors in procedure and judgement. Any recommendation that an untrained individual work on a live panel is, in my opinion, unnecessarily dangerous and an incredibly bad idea. If you cannot shut the panel off, you need an electrician to do this work.
Homeowners are generally comfortable to work in electrical panels because they are blissfully ignorant of the dangers involved. They've probably had one or two mild shocks in their life working with 120 VAC and maybe sparked a few wires at an outlet box. The hazard from shock/electrocution isn't that much greater in an electrical panel than it is anywhere else. Homeowners are generally not aware of the increased arc flash potential inside an electrical panel because the danger is not intuitive. The flashes that are created at an electrical outlet box are greatly reduced by two factors, both related to the small size of the wires involved. One is the impedance that even 20 to 25 feet of #12 or 14 wire adds to the fault circuit. Fault currents at the average outlet box are only a few hundred amps. Also, the small size wires and low voltage (120V) tend to clear the fault in a very short time as the wire vaporized; frequently faster than the OCPD can open. I've seen plenty of remote shorts that didn't trip the circuit breaker.

In an electrical panel, OTOH, the fault current is limited only by the PoCo transformer impedance and the impedance of the service cables and is typically thousands of amps. Also, this current is generally not protected by any OCPD and is likely to be flowing thru a tool (screwdriver or pliers), not just a very small wire. Even if you shut the main circuit breaker off, the line side mains (the most dangerous) are still live.

I'm a professional and I do work in live electrical panels (no OSHA violation, I'm not an employee) and I have survived an electrical arc flash/blast (by sheer luck). I (now) always wear 20 cal/cm2 clothing, face shield and Class 1 gloves when I work with energized electrical panels. I understand the risks. I just wish most homeowners did the same. I've seen firsthand the burns that come from arc events. They are NOT pretty and they happen instantly.

BTW, in case you think you're safe when the PoCo pulls the meter, I've got great video of arcing due to neighbors neutral current trying to return over the service I was working on with the meter pulled. I've said many times, the only way to be sure not to be injured/killed by electricity is never to touch anything electrical. That just leaves lightning to worry about.

Be safe.

Mark

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Last edited by busman; 04-02-2013 at 09:11 AM.
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