ECN Forum Forums Code Related Discussion NEC & other Code issues Service disco: 6 throws or less

Do double pole circuit breakers count as 1 throw when used to disconnect power from service to meet the requirements of 230.71(a)?? 200 amp service for a workshop (60x40).Will be used for light work(tablesaws, a window unit a/c,lighting etc)I will not be using a main breaker. there will only be 6-8 breakers. whatcha think?? Owner already has squareD 3r panel with no main. I think I can keep it under 6 .
All opinions welcome. Fire Away

Sean - darned if I can find the section at the moment - but a 2-pole or 3-pole breaker (with handle ties) is considered one 'throw' or disconnect.

I believe what you are looking for is in 230.71 (B). Viz.

(B) Single-Pole Units. Two or three single-pole switches or breakers, capable of individual operation, shall be permitted on multiwire circuits, one pole for each ungrounded conductor, as one multipole disconnect, provided they are equipped with handle ties or a master handle to disconnect all conductors of the service with no more than six operations of the hand.

The inspection failure will come from section
408.14 Classification of Panelboards.
Panelboards shall be classified for the purposes of this article as either lighting and appliance branch-circuit panelboards or power panelboards, based on their content. A lighting and appliance branch circuit is a branch circuit that has a connection to the neutral of the panelboard and that has overcurrent protection of 30 amperes or less in one or more conductors.
(A) Lighting and Appliance Branch-Circuit Panelboard. A lighting and appliance branch-circuit panelboard is one having more than 10 percent of its overcurrent devices protecting lighting and appliance branch circuits.

And section

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.

So if this really is a service you will have to provide a one or two breakers or sets of fuses rated at the ampacity of the panel board or less. If the panel is supplied from the service in another building then the feeder breaker will satisfy the requirements of this rule and the six breakers or less will actually be meeting the requirements of

225.33 Maximum Number of Disconnects.
(A) General. The disconnecting means for each supply permitted by 225.30 shall consist of not more than six switches or six circuit breakers mounted in a single enclosure, in a group of separate enclosures, or in or on a switchboard. There shall be no more than six disconnects per supply grouped in any one location.
Exception: For the purposes of this section, disconnecting means used solely for the control circuit of the ground-fault protection system, or the control circuit of the power-operated supply disconnecting means, installed as part of the listed equipment, shall not be considered a supply disconnecting means.
(B) Single-Pole Units. Two or three single-pole switches or breakers capable of individual operation shall be permitted on multiwire circuits, one pole for each ungrounded conductor, as one multipole disconnect, provided they are equipped with handle ties or a master handle to disconnect all ungrounded conductors with no more than six operations of the hand.
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Tom

[This message has been edited by tdhorne (edited 09-21-2002).]

hmmmm.........I see, so this panel is useless to the job at hand? He may need to get a 3r with a main.

[This message has been edited by Sean WB (edited 09-22-2002).]

Sean
Most of the panels in that size have adapters available to use a back fed double pole breaker as the disconnecting means. He could also mount an enclosed 3R breaker or switch outside or a regular enclosed breaker or switch inside were the conductors enter the building if the panel is to be too far from the entry point.
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Tom

or introduce handle ties and/or 2-pole breakers to reduce the number of throws to the magic #6....

Adding handle ties & 2 pole breakers will not help this out. Tom correctly pointed out that this installation will still be in violation of 408.16, a section that is much abused, especially on temporary services.

If you elect to use a back fed 2 pole breaker in your panel, make sure you are in compliance with 408.16(F) which requires a means of securing the breaker in place so that it takes more than a pull to remove it.

Tom