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Electrical Code - USA Commercial or Residential 1999 / 2002 / 2005 versions - for UNITED STATES

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  #1   IP: 65.203.178.1
Old November 20th, 2009, 07:41 AM
Paul Kluesner Paul Kluesner is offline
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Default Maximum number of breakers in a switchboard

I have been told that if I have more than six breakers or disconnects in a switchboard that I need a main breaker. The switchboard is 575 volts, 2000 amp bus. A main breaker would increase my cost significantly. 230.71 mentions the max number of disconnects but it doesn't say I need a main breaker.

Can anyone offer me some help?
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  #2   IP: 75.207.28.126
Old November 20th, 2009, 10:21 AM
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Wgoodrich Wgoodrich is offline
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The answer to the question word for word as you asked it is yes and no. Reason for this is conditions you did not mention. If this panel is a main service rated panel in a main structure with no previous overcurrent device aka breaker or fuse then the 6 disconnect rule applies. Each breaker in that panel would be considered as a mian service rated disconnect with 6 being the maximum you can have. The above statement for example would be a panel fed directly from a service company meterbase and not prior fuse or breaker. A second example of this being a yes answer would be if you are feeding a detached accessory structure from a main structure. The fuse or breaker installed in that accessory detached structure where the feeder entered would have a maximum of 6 disconnect rules including the number of breakers in a main lug only panel without a main breaker.

If the question you asked is concerning a panel that is a slave from a main service rated panel in the same building as that main service rated panel the answer would be no a main would not be required and the 6 disconnect rule would not apply. This is because there is a fuse or breaker in the same building that can be used as the main form of disconnect and this panel being a slave of the main panel would be a subpanel thus not being a main service rated panel. If your panel is a slave of a main service rated panel being a sub panel of that main panel then there would be no limit.

Even though breakers in a panel are circuit breakers if there is no other means of shutting off that panel then the 6 disconnect rule would apply. Sub panels have a breaker in a panel feeding power to that subpanel that will shut of that entire subpanel then the 6 disconnect rule does not apply.

They often call the 6 disconnect rule in other words maximum of 6 sweeps of the hand to shut down power coming from that panel.

Hope this helps

Wg
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  #3   IP: 209.91.54.95
Old November 20th, 2009, 10:35 AM
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Ohm1 Ohm1 is offline
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Quote:
Originally Posted by Paul Kluesner View Post
I have been told that if I have more than six breakers or disconnects in a switchboard that I need a main breaker. The switchboard is 575 volts, 2000 amp bus. A main breaker would increase my cost significantly. 230.71 mentions the max number of disconnects but it doesn't say I need a main breaker.

Can anyone offer me some help?


Need more information.

To add:
For services, If we look at 230.71(A), you will find that it presents that no more than 6 handles shall disconnect a service from the structure being served.

Yet, for a detached building--being fed from another. You should look at Part 2 of NEC 225 . (Special attention to 225.36)
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  #4   IP: 65.203.178.1
Old November 23rd, 2009, 06:36 AM
Paul Kluesner Paul Kluesner is offline
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Thanks for the replies. This switchboard is being fed by five generator strings, the 6th breaker is for a capacitor bank. I hope this is enough information.
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  #5   IP: 75.205.55.133
Old November 24th, 2009, 02:03 PM
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Wgoodrich Wgoodrich is offline
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Now you caused much more confusion and lack of info needed. What do you mean by 5 generator leads. Are you saying you have hooked five generators to five different breakers to feed this panel ? What is the capacitor connection used for ?

Wg
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  #6   IP: 72.38.178.108
Old November 24th, 2009, 02:16 PM
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This sounds way beyond DIY which this site is for. Sounds like you have 6 generators powering a site with a capacitor bank for power factor correction.
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  #7   IP: 96.50.79.109
Old November 24th, 2009, 06:52 PM
moto moto is offline
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It was way beyond DIY when he mentioned 575 volts and 2000 amps....
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  #8   IP: 71.174.88.209
Old November 25th, 2009, 05:50 AM
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What I can't have 2,000a residential service ?

I have a big Christmas display !!
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Last edited by scuba_dave : November 25th, 2009 at 08:20 AM.
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  #9   IP: 209.91.54.95
Old November 25th, 2009, 08:04 AM
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I agree, if the OP is not a Licensed Electrician (Contractor). Yet, if the OP an electrical professional, then we are here to help.
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  #10   IP: 64.83.217.86
Old November 25th, 2009, 04:30 PM
junkcollector junkcollector is offline
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I thought this site was for professionals and DIY'ers alike. Heck we even have a Commercial / industrial section.
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