Service Equipment Disconnect. What to Use?

Status
Not open for further replies.
O

Ozymandias

Member
Location
Missouri
A 200A panel with a service disconnect is in the bathroom of a retail space. This a tenant finish, bathroom is to remain as existing. Inspector doesn't want it there. We battle it out with our NEC 2011 codebooks. He wins by citing 230.70(A)(2). While the architect argues grandfather it with the city's planning department I am looking at the possibility of installing a service disconnect outside adjacent to the meter can and turning the box inside into a panel board satisfying the inspector. My questions:
This is an ITE electrical box, when I do this I must float both the grounding bars and neutral bars thus separating them from each other, correct?
I must somehow exit the meter can thru the bottom hit my disconnect and use the meter can as a raceway to get into the panel board with my conductors, right?
Or must I set a trough under the meter can and service disconnect and run conductors to and from to utilize the space?
All the bonding and grounding happens at the disconnect at this point, and three wires from meter can to disco?
What are my choices in service disconnects?
Thanks for your input!
 
augie47

augie47

Moderator
Staff member
Location
Tennessee
Occupation
State Electrical Inspector (Retired)
The choice is an open book. Since it's retail space its possible you might have a fault-current higher than 10k. That's the 1st thing I'd check and if the SCA is greater than 10K be sure your new service disconnect is rated accordingly.
In routing your conductors from your meter be sure you don't share any raceway with service (unprotected) and feeder (protected) conductors.
 
O

Ozymandias

Member
Location
Missouri
Augie47, that's interesting, so a retail space may have a larger fault current due to space classification or there's some design calculations that have to be made to arrive to that? This will be a hair salon with a small retail section if that makes a difference. Duly noted on the raceway, and Smart those disco's fit the bill all I need is to make a choice. Thanks to both!
 
augie47

augie47

Moderator
Staff member
Location
Tennessee
Occupation
State Electrical Inspector (Retired)
The short-circuit-amps-available is based to a great degree on the size of the utility transformer. It seldom becomes a problem with a limited load on the transformer (such as a limited number of dwelling units or small commercial).
Locally when the total size of the service disconnects connected to a single utility source exceeds 400 amps we take a closer look at it.
 
G

GerryB

Senior Member
Location
woodbridge, ct. USA
Ozymandias said:
A 200A panel with a service disconnect is in the bathroom of a retail space. This a tenant finish, bathroom is to remain as existing. Inspector doesn't want it there. We battle it out with our NEC 2011 codebooks. He wins by citing 230.70(A)(2). While the architect argues grandfather it with the city's planning department I am looking at the possibility of installing a service disconnect outside adjacent to the meter can and turning the box inside into a panel board satisfying the inspector. My questions:
This is an ITE electrical box, when I do this I must float both the grounding bars and neutral bars thus separating them from each other, correct?
I must somehow exit the meter can thru the bottom hit my disconnect and use the meter can as a raceway to get into the panel board with my conductors, right?
Or must I set a trough under the meter can and service disconnect and run conductors to and from to utilize the space?
All the bonding and grounding happens at the disconnect at this point, and three wires from meter can to disco?
What are my choices in service disconnects?
Thanks for your input!
Click to expand...
What about 240.24(2)(E) This is quoted to allow panels in commercial bathroom space
 
O

Ozymandias

Member
Location
Missouri
After a closer look I realized I am dealing with a 3P/4W 120/208 system, a 225 amp rated panel with a 200A main and 30 spaces. Would an outdoor service disconnect applicable for this situation have an MCB or fuses? The indoor main breaker panel looks beat up, would an MLO be right for this situation? I still have to figure out the available fault current available for the building as augie47 suggested. Let's say as an example interrupting rating of the building is 30,000 amps can the disconnect MCB be rated for 30,000 amps and MLO OCDPs rated for 10,000 amps as usual or 30,000 as the disco's MCB? I don't know if this job will materialize but now I am curious about all this, thanks!
 
kwired

kwired

Electron manager
Location
NE Nebraska
Ozymandias said:
After a closer look I realized I am dealing with a 3P/4W 120/208 system, a 225 amp rated panel with a 200A main and 30 spaces. Would an outdoor service disconnect applicable for this situation have an MCB or fuses? The indoor main breaker panel looks beat up, would an MLO be right for this situation? I still have to figure out the available fault current available for the building as augie47 suggested. Let's say as an example interrupting rating of the building is 30,000 amps can the disconnect MCB be rated for 30,000 amps and MLO OCDPs rated for 10,000 amps as usual or 30,000 as the disco's MCB? I don't know if this job will materialize but now I am curious about all this, thanks!
Click to expand...

For you to have over 10k fault current you likely need at least 112.5 kVA transformer and very little distance between it and your service. Just 25 feet of 200 amp conductor will make a difference on how much current is available at the load end of the conductors.

That said if you still have a high available fault current use of main breaker that is same manufacturer as your panel will often have been tested for series rating as well as having series ratings with fuses as the main overcurrent device.
 
Status
Not open for further replies.
Top