Would I be correct to say that a detached garage on the same property as a one family dwelling with one feeder run to it as required by 225.30 shall have a disconnecting means out at the garage to shut down the sub-panel and that the minimum size of that feeder can't be smaller than 60 amp as required by 225.39(D)where the building will have more than 2 branch circuits???

Yes on the disconnect. On the 225.39(D) issue, that just says the "disconnect" has to be able to open 60a, not that the feeder itself has to be 60a.
Clear as mud huh?

The disconnect that is required by 225.31 must also be "suitable for use as service equipment" as stated in 225.36...so would a 20 circuit main lug panelboard with the feeder connected to a 60 amp 2-pole breaker pluged into the buss be considered as suitable as service equipment or should a listed main breaker panelboard be used at the detached garage?

Your good to go with the back fed 60 as long as you remember to secure the breaker in place.

Also if you are installing a total of less than 6 breakers you can forget about the back fed 60.

Up to 6 throws of the hand can be the disconnect, regardless of the panel size.

Bob

Hi Bob...so the 60 amp backfeed main should be bolted in place...but the 6 breakers or less don't need to be bolted in place?

shortcircuit

AS Bob said
if a device is back fed it must be secured to avoid poping out if the panel cover is removed for service.

408.16 (F) Back-Fed Devices. Plug-in-type overcurrent protection devices or plug-in type-main lug assemblies that are backfed and used to terminate field-installed ungrounded supply conductors shall be secured in place by an additional fastener that requires other than a pull to release the device from the mounting means on the panel.

Don't for get the requirements for gounding second buildings or structures, Article 250.32. Esp if you have interconnecting metal raceways or water piping)

do you need 20 circuits??

[This message has been edited by cpal (edited 08-20-2004).]

Hey cpal...OK I understand about bolting in the main and the grounding requirements...but what about the 6 breakers as the disconnecting means...they need not be bolted in as you describe above?A 20 circuit panel will be used.

thanx, shortcircuit

The bolting is to prevent the breaker from being pulled off and having live clips on the rear. In the 6-throws situation, the bus is live but if you remove a breaker, the breaker is dead.

In ordert to use a back fed breaker as the required building disconnecting means the panel must be listed as service equipment with a back fed breaker. Check the panels labeling that it is listed in that configuration.
--
Tom Horne

It is true that you can forget about the backfed main with 6 breakers or less but only if it is not a lighting and appliance branch circuit panel board. 408.16(A) Correct? or does exception 1 change this?

[This message has been edited by Buck33k (edited 08-20-2004).]

Sorry I have not gotten back to this.

by tdhorne

Tom I am not deputing that but what article requires that? 110.3(B)?

Is there a panel that can not be backfed and why?

by Buck33k

Buck I do not see how this changes anything, the overcurrent protection can be (and usually is) taken care of at the panel the feed originates from.

shortcircuit What I was trying to get at but was in to much of a hurry to get across before.

1)You could install a main breaker panel.

2)You could backfed a main lug panel, with a secured breaker and following Tom's post.

3)If you can live with 6 circuits or less you can install a main lug panel, fed it from the lugs and use the 6 or less breakers as the disconnecting means. They will not have to be secured because they are not back fed.

Remember the 225.31 does not require the panel to be shut down only the conductors.

Bob

Thanx for your interpertations everyone...they have all shed light on the issue.
So if the 20 circuit panel is installed with only 6 branch circuit overcurrent devices, it does'nt require a main disconnect...untill the next electrician comes along and wants to add another circuit, then he must install a main breaker to comply with 225.31

Yes that is correct looking at it from just a code standpoint you can install the 20 circuit panel with only 6 breakers and be code compliant.

It would be up to the next person not to violate the code.

I respectfully disagree with the blanket statment of allowing 6 mains in this panel. We need to look at 408.14(A) and 408.16(A) and decide if we are limited to a maximum of 2 mains.

Sorry -Meant to include 408.14, which is the classification of panels.https://www.electrical-contractor.net/ubb/icons/icon12.gif

George

I disagree. The overcurrent protection of this panel is the feeder breaker at the house. The overcurrent protection is permitted to be in the panel or anywhere on the supply side of the panel. The only issue here is the number of disconnects permitted. As the others have said you can not have more that 6 breakers in this panel unless a main breaker or other disconnect is installed. The disconnect could be a non-fused switch.

Curt

Thats where I went wrong in my post. The garage is fed from the house with OCP. If Shortcircuits garage had its own service and the six breakers were the only disconnect, then 408.16(B) would apply. Hope I got it right this time!

Curt- Your correct. I owe you a donut and coffee. Next time your in a Krispy Kreme have one on me. :-)
I was thinking along the lines of providing overcurrent protection for the panel.

WARNING - I don't have my Code with me, so I can't look this up myself. Apologies in advance for possible idiot factor.

The garage isn't operating under independent service... it's being fed from an OCP inside the house.

With one throw of the hand, you can D/C everything by turning the 60A in the house off, correct? (and secure by LOTO since no line-of-sight if needed)

So why would this still fall under the "6-throw" limit, if _not_ fed by a service separate fro the house?

Doug I like the clear warning.

This application is covered in Article 225 Outside Branch Circuits and Feeders.

225.31 is the section that requires a disconnect and 225.32 tells us where the disconnect has to be. The disconnecting means shall be either inside or outside at a readily accessible location nearest the point of entrance of the conductors. There are also some exceptions but they are not applicable to a detached garage.

225.33 limits us to 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 as the disconnecting means.

Bob

The answer lies in the requirement that the disconnecting means be marked as "suitable for use as service equipment" The marking would read suitable for use as service equipment when a (XXX) breaker is installed using kit #... Since that is an instructtion that is included in the listing or labeling then you must meet that condition for the panel to be "suitable for use as service equipment." In other words if the label were to call for a QOM1100 as the main breaker then using a QO two pole sixty ampere breaker with a tie down kit would not be in compliance with instructions that are "included in the listing or lableing." You cannot violate the instructions on the labeling and still claim that the panel in question continues to be suitable for use as service equipment.

[This message has been edited by tdhorne (edited 08-29-2004).]

[This message has been edited by tdhorne (edited 08-30-2004).]