Bolt-on vs. Plug-in (Panelboard and Circuit Breaker)

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nikhilub

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Hello,

I researched the forum and NEC and I am convinced that there is not really a requirement that a load center / panelboard has to have bolt-on breakers. [Although we all know that bolt-on breakers are more preferred].

Now, in an Industrial environment, I think going conservative is only going to do good and for safety. Is there any code that specifies to use a superior quality equipment "when available" for Industrial environment ?

I guess, personally speaking, not too comfortable to see "Home depot" quality load center in an Industrial environment. Cost savings is one thing, but lets keep that point apart for Industrial environment.

Thanks,
 
I prefer bolt on in commercial /industrial installations although not a requirement.
 
You can't get plug-on breakers / load centers for voltages over 240V or currents over 400A making them generally unsuited for industrial applications. Most large industrials with Engineering standards will not allow them, they are generally considered less reliable than bolt-on because of the greater likelihood of being exposed to contaminants that will affect the plug-on connections, something not encountered in the average residence..
 
Jraef said:
...they are generally considered less reliable than bolt-on because of the greater likelihood of being exposed to contaminants that will affect the plug-on connections...
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32 years in this industry I have never heard of this 'old wives tale'.

The bolt is not part of the current carrying connection, so a contaminated busbar would be a poor connection regardless.

Plug-on connections have been used with 600V fusible panelboards for many decades.

I cannot remember the last time I saw an industrial busway system that did not have plug-in device
 
Ge makes a similar plug in breaker like I-Line, but plugs in from the front. Square D also has a 277/480 volt panelboard (NEHB I think) that takes bolt or plug in breakers, as well as a 120/208 volt panelboard that takes both (NQOD)
 
hillbilly1 said:
Ge makes a similar plug in breaker like I-Line, but plugs in from the front. Square D also has a 277/480 volt panelboard (NEHB I think) that takes bolt or plug in breakers, as well as a 120/208 volt panelboard that takes both (NQOD)
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NEHB is correct although I think they may not make he panelboard anymore. Someone will probably correct me though. Our plant has several NEHB panels that I curse every time I have to open one. I think above a certain amperage they are bolt-on only but I can't remember what that level is.
 
You may need a higher AIC rating and most plug in breakers are only available at 10k.
 
sii said:
NEHB is correct although I think they may not make he panelboard anymore. Someone will probably correct me though. Our plant has several NEHB panels that I curse every time I have to open one. I think above a certain amperage they are bolt-on only but I can't remember what that level is.
Click to expand...
The panel is obsolete, but you can get the breakers.
60A was the largest plug-on(?)
 
One of the differences I never understood is, if you buy the breakers separately, the bolt-in breakers are way more expensive. But on a bid job, when you send the panels to Square D for pricing, there isn't really any cost savings on specifying QO breakers instead of QOB. The only cost savings would be the 10 minutes or so it takes to screw 30 or 40 breakers into the panel.
 
LOL, breaker pricing is nuts, we have ordered entire panel-boards loaded with breakers only to get the breakers cheaper and the panel-board went in the dumpster.

Bus duct switches the same way, much cheaper if you buy them with bus duct.
 
Same with MCC buckets. Much cheaper when you buy the MCC with the buckets in them. I don't know how many MCC sections I have scrapped out because of the pricing.
And the buckets are plug in up to at least a size 4 starter.
 
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