Re: sub panel questions
Originally posted by david:
I will probably get shot down here. If you carry this logic through you would have electrical inspectors passing main lug 40 space panels (no main) for dwelling services as long as there are no more than six breakers installed at the time of the inspection. Before you say it, I agree no electrician would do that. I am only trying to make a point. You are saying if a homeowner installs this I should pass it. You are saying it is code compliant.
I ask again is the panel listed as a service disconnect with out a main?
408.16 Over current Protection.
(A) Lighting and Appliance Branch-Circuit Panel board Individually Protected. Each lighting and appliance branch-circuit panel board shall be individually protected on the supply side by not more than two main circuit breakers or two sets of fuses having a combined rating not greater than that of the panel board.
And I know this always gets thrown into the discussion, but this panel would also be classified a Lighting and Appliance panel board, limiting the main to max. two disconnects.
David
Your question about the listing is very apropos but I haven't purchased one of those smaller panels in years that was not listed as service equipment when certain conditions are met. The conditions I have encountered are that not more than six breakers are installed or that a back fed main be installed with an anchor kit. In this case the first condition is met. The fact that you might install more breakers later is a non issue. As IWIRE has already pointed out any trough and disconnect service can have additional disconnects installed after the inspector departs. Some idiot could also remove the main breaker and replace it with lugs in any convertible panel assembly. You can only inspect what is there at the time of inspection. If you turn down the installation based on the likelihood of a future violation you are ignoring a basic principal of law. No agent of the government can take action against a future bad act. The phrase is somewhat over used but that truly is black letter law.
The feeder breaker meets the requirement for not more than two disconnecting means for a lighting and appliance panelboard. The language of exception one clearly exempts panels when "the panelboard feeder has overcurrent protection not greater than the rating of the panelboard."
I have used the six breaker rule to update homes that have multiple sub panels when the owners are elderly or disabled on fixed incomes. The solution is not elegant but installing a twelve slot MLO panel that is listed for use as service equipment when not more that six main disconnecting means are installed and then running individual feeders and branch circuits to existing panelboards or larger loads can cut the cost of a heavy up in half. You only have to make sure that you convert the original service equipment panel to a four wire feeder supplied panelboard by installing the appropriate Buss bar and terminating the neutrals and grounds onto the correct bar. I've had two inspectors who really hated it but both eventually agreed that it was code compliant. The SquareD panel I use for this is available with a QOM2 main breaker but I do not want a single main breaker when the equipment supplies the current to a water pump that will also be used for first aid firefighting.
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Tom
408.16 Overcurrent Protection.
(A) Lighting and Appliance Branch-Circuit Panelboard Individually Protected. Each lighting and appliance branch-circuit panelboard shall be individually protected on the supply side by not more than two main circuit breakers or two sets of fuses having a combined rating not greater than that of the panelboard.
Exception No. 1: Individual protection for a lighting and appliance panelboard shall not be required if the panelboard feeder has overcurrent protection not greater than the rating of the panelboard.
[ March 10, 2003, 11:59 AM: Message edited by: hornetd ]
I am passionately opposed to any tolerance for inspectors making up amendments to the code as they encounter situations that do not fit their personal views of what the best practice would be. This is exactly the same thing as a police officer trying to ticket you for driving to endanger because you were driving at a slower speed than he/she thought was safe when you are going at a speed that is between the minimum and maximum speeds allowed by law.