Is it ever ok to put a bolt on breaker in hot?

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ram11379

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I have a old Westignhouse panel at a school I am trying to tap off of. It is a 250 amp 3-phase 208v sub with bolt on breakers. I am wanting to install a 100 amp sub panel for a server room off this panel.

My question is at what point is it considered not a good idea anymore? With all our knowledge and safety concerns am I to never put in a bolt on without killing that panel first? Should I even consider installing this hot or is it now considered an automatic NO?
 
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jim dungar

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PE (Retired) - Power Systems
I know of no manufacturer that says you can install their equipment while it is energized.
 
2

220/221

Senior Member
Location
AZ
My question is at what point is it considered not a good idea anymore?
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It's never a "good idea" but it is done every day.

The official stance is no.

Some people use voltage to draw the line and wouldn't bolt on a 480V breaker hot. Some use amperage and would bolt to a 200A panel bus but not to a service section. Logistics play an important role also. Some new panels have plenty of working space in and around them but some conditions are not safe at all.

My personal criteria changes toward caution a little more every day. I remember a decade ago, laying down on the ground installing a 200A switch on a live bus with a taped up ratchet/extension. Not the smartest thing I have ever done but at the time I felt it was an acceptable risk. I wouldn't do it again unless it was a life or death emergency. I will however still bolt a 120/240V breaker onto a bus in a newer panel.
 
cschmid

cschmid

Senior Member
Location
Northern cold country
ram11379 said:
I have a old Westignhouse panel at a school I am trying to tap off of. It is a 250 amp 3-phase 208v sub with bolt on breakers. I am wanting to install a 100 amp sub panel for a server room off this panel.

My question is at what point is it considered not a good idea anymore? With all our knowledge and safety concerns am I to never put in a bolt on without killing that panel first? Should I even consider installing this hot or is it now considered an automatic NO?
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wow a tricky question and we have just discussed the working live issue. is there a reason you want to do this live? has there been an arc fault assesment? have you been properly trained to do live work?
 
quogueelectric

quogueelectric

Senior Member
Location
new york
I have done it thousands of times yet new training has made me rethink what I am risking if I were to make a mistake in a large gear. Is it worth taking the risk?? you have to ask yourself if it is worth the risk of losing life to cover up poor planing. I racked in some rather large breakers this week and all that I was thinking was that u tube video where the gear blew up and killed the electrician. I had a scheduled shutdown at 5am monday morning to change out 2 breakers BIG breakers. 2 hrs overtime but the gear was shut down that early just minor glitches as there was no crane or dolly so we had to horse the breakers up and they were heavy. You will be the hero until you make a mistake and then you are a zero.
 
76nemo

76nemo

Senior Member
Location
Ogdensburg, NY
After 15 beers once the campfire goes out, and you're tired, is it okay to drive 12 miles home to your house? Very possibly, but what if you're overtired, and you nod off to enter into the opposing lane and kill a family of three?????????? Hell. what's the difference, somebody lost their Father. Either circumstance, you could of avoided it, don't take your chances!!!!!!!
 
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ram11379

Member
Thanks for the replies folks.

Thanks for the replies folks.

I appreciate the time you all put into this and the general feeling of everyone has pushed me off the fence. I will go in after hours and kill the panel. Not worth the risk.:)
 
Pierre C Belarge

Pierre C Belarge

Senior Member
Location
Westchester County, New York
quogueelectric said:
I have done it thousands of times yet new training has made me rethink what I am risking if I were to make a mistake in a large gear. Is it worth taking the risk?? you have to ask yourself if it is worth the risk of losing life to cover up poor planing. I racked in some rather large breakers this week and all that I was thinking was that u tube video where the gear blew up and killed the electrician. I had a scheduled shutdown at 5am monday morning to change out 2 breakers BIG breakers. 2 hrs overtime but the gear was shut down that early just minor glitches as there was no crane or dolly so we had to horse the breakers up and they were heavy. You will be the hero until you make a mistake and then you are a zero.
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Sherman
You may wnat to cechk yuor tag at the btotom of the pgae, the spnleilg is teirrble.
 
cschmid

cschmid

Senior Member
Location
Northern cold country
ram11379 said:
I have a old Westignhouse panel at a school I am trying to tap off of. It is a 250 amp 3-phase 208v sub with bolt on breakers. I am wanting to install a 100 amp sub panel for a server room off this panel.

My question is at what point is it considered not a good idea anymore? With all our knowledge and safety concerns am I to never put in a bolt on without killing that panel first? Should I even consider installing this hot or is it now considered an automatic NO?
Click to expand...


You know one thing you should always remember is if you have doubts then you should never do it.
 
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petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
My guess is that somewhere along the way, we are going to have to figure out how to deal with all the NFPA70E requirements that does not involve shutting down large parts of installations for what used to routinely be done without having a shutdown.

Maybe better designed equipment will be the answer. Or some kind of robotic aid.

Will the robot have to get a jouneyman's card before he works on electrical systems? :)
 
cowboyjwc

cowboyjwc

Moderator
Staff member
Location
Simi Valley, CA
"Hey guys! Watch this!" Pretty much the same as...."I've done it a hundred times and never had a problem."

As I got older I thought I was getting to be more of a coward, then I realized that I was just getting smarter. Don't you hate it when your parents were right?:grin:
 
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