help on grouping disconnects

[rickl]

hi
i need some help on this subject, the more i read the more confused i get, i'm getting different answers for the ahj's in my area.
here is the situation:
i have one new house where the homeowner wants the 400 amp CT can and meter base mounted on the outside of his pump house, from the CT can i will feed 2 200 amp main breaker panels mounted inside his house ( 75' away)and the pump house with a 60 amp main breaker panel, and he wants to also feed a shop in the future out of the CT can.
I was a little confused if i needed to group all of the disconnect. so i called the ahj, one said no, as long as everything is on the outside of the building you don't need to group the disconnect. then today i called and got another ahj and he said yes i would have to group the disconnect if there mounted on the outside of the building, but if i mounted the CT can & meter on a pole then i wouldn't have to group the disconnect. who's right
any insight would be greatly appreciated

 

[benaround]

Re: help on grouping disconnects

rickl,

Without having a main disconnect as far as I know the service disconnects have to be grouped,as in one location. Not nesseceraly at the CT enclosure but that would be ok.

So 2-200amp and 1-60amp need to be grouped.

frank

 

[hurk27]

Re: help on grouping disconnects

The requirement of disconnects only pertain to each building receiving power. If you feed two 200 amp feeds to the house then this is one building and it would be required that each 200 amp feed have a disconnect either outside of just inside at the point of entrance. If you feed the pump house then any conductors that "enter" that pump house will have to follow the same rule as above. The same goes for any building.

Conductors that do not penetrate the outside wall are not "entering " the building.

230.70 General.
Means shall be provided to disconnect all conductors in a building or other structure from the service-entrance conductors.

The bold is by me to point out the if they are outside then they are not "in" the building and there is no requirement for a disconnect.

This has been one of my pet-peeves with inspectors requiring a disconnect for a pole mounted service as how can the conductors be "IN" the pole

Read article 230 from .70 through 82 and also 230.40.
230.40 exception 3 allows what you are doing:

Exception No. 3: A single-family dwelling unit and a separate structure shall be permitted to have one set of service-entrance conductors run to each from a single service drop or lateral.

If disconnects were required then this exception would not make any sense? They would no longer be service entrance conductor's!

[ July 11, 2005, 06:54 PM: Message edited by: hurk27 ]

 

[suemarkp]

Re: help on grouping disconnects

You need a disconnect for every part of the service that is "in" the pump building. I would think that service wires going from the CT can to the house are not "in" the building if they are always along the outside wall, so they don't need a disconnect there (but you could choose to provide one). You certainly need a disconnect for the 60A panel supplying the pump house.

If you choose to install disconnects for the house and shop at the pump house, they need to be grouped with the 60A pump house panel disconnect (adjacent to each other and on the same side of the wall).

So the answer depends on what the meaning of "in" is or whether you are choosing to install disconnects that may not be required.

 

[hess]

Re: help on grouping disconnects

your first ahj answer is correct.
basically you have multible services that is served by one meter.

 

[hurk27]

Re: help on grouping disconnects

By suemarkp: If you choose to install disconnects for the house and shop at the pump house

But then he would still have to install disconnects at each building again,
Because of 225.31? would that make any sense?

 

[benaround]

Re: help on grouping disconnects

hurk27,

If the word 'in' is not used, what other word could replace it?

frank

 

[rickl]

Re: help on grouping disconnects

this is my plans
mount 400-amp ct can and meter base on pump house outside wall, feed 60-amp main breaker panel on the inside of the pump house. then feed 2 200-amp main breaker panels from ct can to inside the house (these will be grouped and just inside at the point of entrance). then in the future add a 100 amp main breaker panel in the new shop feed from the ct can. I hope this make sense to every one. what i think the problem is with the second ahj is his interpretation of 230.6 conductor considered outside of building,heck maybe he's is right
thanks for all the insight

 

[LarryFine]

Re: help on grouping disconnects

Rick, that sounds right to me: the disconnect(s) for each building at the point of entrance for that building.

 

[hurk27]

Re: help on grouping disconnects

Frank who said anything about not using the word "in" ?
There are probley more than one word to discribe "in" like inside, interror,Etc... But I was using it as it is in the code.
The problem is some can't see that little two letter word and think every place there is a meter there should be a disconnect. :roll:

 

[hurk27]

Re: help on grouping disconnects

Oh by the way Rick that sounds like a plan. I would print this thread and show it to your AHJ to see if they have any local code that might require a disconnect for the whole service, but from what they said it dosent sound like it.

 

[curt swartz]

Re: help on grouping disconnects

Are you planning to run 2-200 amp feeders to the house or 1-400 amp feeder?

 

[rickl]

Re: help on grouping disconnects

2 200 amp panel unless you have a cheaper solution

 

[curt swartz]

Re: help on grouping disconnects

I understand you are planning to use 2-200 amp panels but I was referring to the feeders to the dwelling.

225.30 Number of Supplies
Where more than one building or other structure is on the same property and under single management, each additional building or other structure that is served by a branch circuit or feeder on the load side of the service disconnecting means shall be supplied by only one feeder or branch circuit unless permitted in 225.30(A) through (E). For the purpose of this section, a multiwire branch circuit shall be considered a single circuit.

(A) Special Conditions Additional feeders or branch circuits shall be permitted to supply the following:

(1)Fire pumps
(2)Emergency systems
(3)Legally required standby systems
(4)Optional standby systems
(5)Parallel power production systems
(6)Systems designed for connection to multiple sources of supply for the purpose of enhanced reliability

(B) Special Occupancies By special permission, additional feeders or branch circuits shall be permitted for either of the following:

(1) Multiple-occupancy buildings where there is no space available for supply equipment accessible to all occupants
(2) A single building or other structure sufficiently large to make two or more supplies necessary

(C) Capacity Requirements Additional feeders or branch circuits shall be permitted where the capacity requirements are in excess of 2000 amperes at a supply voltage of 600 volts or less.

(D) Different Characteristics Additional feeders or branch circuits shall be permitted for different voltages, frequencies, or phases or for different uses, such as control of outside lighting from multiple locations.

(E) Documented Switching Procedures Additional feeders or branch circuits shall be permitted to supply installations under single management where documented safe switching procedures are established and maintained for disconnection.

 

[rickl]

Re: help on grouping disconnects

2 4/0-4/0-2/0 alum feeders, the house is 3200 square feet calculated load around 225 amps. wouldn't 225.30 b (2) allow me to feed this house with 2 feeders.

 

[curt swartz]

Re: help on grouping disconnects

I don?t think a 3200? single family dwelling qualifies as a special occupancy. You also must get special permission from the AHJ . If I was the AHJ I would not accept it since you could easily supply this house with one feeder but you are choosing to use 2 because of cost. You could pull one feeder to house and tap of the feeder for the 2-200 amp panels. I?m not sure this would save much over using a single 400 amp panel.

 

[George Stolz]

Re: help on grouping disconnects

I would tend to agree. Why not just install one?

 

[derf48]

Re: help on grouping disconnects

Remember it is not a feeder unless you put a disconnect at the pump house for the dwelling unit. The conductors entering the dwelling from the CT are service laterals and 2 sets are permitted per 230.40 ex #2.

Fred Bender

 

[volt101]

Re: help on grouping disconnects

Fred I agree!
Also, just to bring up an already maid point.

Exception No. 3: A single-family dwelling unit and a separate structure shall be permitted to have one set of service-entrance conductors run to each from a single service drop or lateral.

Again, if the disco was on one of the structures, it would be a feeder to the other.

One panel at the pump house, two panels in the home are fine as long as the two at the house are grouped.

Jim

 

[hurk27]

Re: help on grouping disconnects

Rick you will still have only one service it doesn't matter how many disconnect you have and article 255 does not enter the picture if these two 200 amp main breaker panels are fed directly from the CT can or meter. Here we use a 320 meter, which is the limit any higher we need CT but I have done many installs just like yours with no problem, well except one inspector which the state AHJ had to straighten out but after that it is the best cost efficient way to do it. This is also how we do garages when they want a 100 amp or more panel in it. 320 meter on the house with double lugs and feed the garage from the meter which treats the panel at the garage just like a service.