Service over current protecion

Status
Not open for further replies.
P

PLR

Member
600 AMP. 120/240 v 3 ph service

Paralleled 350 MCM copper from the CT Cabinet to A 600 AMP. non fused disconnect . Paralleled 350's from disconnect to 12"x 12"x 5'
trough.
each set of 350's are tapped to 3-4/0 copper which feed 3 separate 200 AMP. main breaker panels. Neutrals are run the same way.

My question is, if a transfer switch is added after the non fused disconnect would it not have to have over current protection.
 
T

texie

Senior Member
Location
Fort Collins, Colorado
Occupation
Electrician, Contractor, Inspector
It would have to be SUSE rated on the line side of the 3 200 amp main disconnects. I'm wondering what the non-fusible disconnect is for?
 
P

PLR

Member
The disconnect is outside of building next to ct cabinet, trough is next to disconnect outside. Tap conductors are nippled through wall to
the 3 - 200 amp main breaker panels.
 
H

hurk27

Senior Member
Location
Portage, Indiana NEC: 2008
Yes the transfer switches ahead of the service disconnect must be service rated which would include OCPDs and disconnect which then make them become the service disconnect 230.91, also this means that the down stream panels are no longer the service disconnects as they are now sub-panels and all GEC's will have to be made to the transfer switch or if you change out the disconnect to a fusible one then it will be the service disconnect point, also the MBJ's will have to be removed from these panels as well as the separating of the grounding and neutrals

This installation makes no sense, why keep paralleling the conductors to the trough when they could have run separate 3/0 conductors to each panel from the CT's or at least the disconnect? why the 4/0 copper for a 200 amp panel?, I understand why they used the disconnect if the main breaker panels didn't meet the grouping requirements of 230.72

When I do services I now keep generators in mind and land all my EGC's on a separate grounding bar so all I have to do if a service rated transfer switch is installed is remove the MBJ then back feed the GEs from the ground rod and disconnect the other end in the existing service panel, or in the case of a CT cabinet run them to it from the start.

Some of these larger disconnects all you have to do is get the fuse block kit from the manufacture to add them to the disconnect that also come with a new set of labels to put in them, and presto you have a service rated disconnect without re-piping.
 
iwire

iwire

Moderator
Staff member
Location
Massachusetts
hurk27 said:
Yes the transfer switches ahead of the service disconnect must be service rated which would include OCPDs and disconnect which then make them become the service disconnect 230.91,
Click to expand...

Just a small point, OCPDs are not required for a transfer switch to be service equipment.

They can have OCPDs, and many do but it is not a code or listing requirement.

The OCPDs can be located directly adjacent too the service disconnecting means.
 
Smart $

Smart $

Esteemed Member
Location
Ohio
iwire said:
Just a small point, OCPDs are not required for a transfer switch to be service equipment.

They can have OCPDs, and many do but it is not a code or listing requirement.

The OCPDs can be located directly adjacent too the service disconnecting means.
Click to expand...
Quite true... but is there any advantage in not having integral ocp?

Without integral disconnect/ocp can you actually have an ATS on the line side of or be the disconnecting means? I know there are MTS's with center off that can serve as the disconnecting means.

What would you use for adjacent ocp that would be an advantage over integral ocp? The only situation I can think of at present is perhaps if an MTS with integral ocp enclosure was too large for the available space, and an adjacent ocp enclosure was not...???
 
Smart $

Smart $

Esteemed Member
Location
Ohio
iwire said:
None that I can think of but that had nothing to do with my point which was do not assume an ATS is not service rated due to a lack of OCPDs.
Click to expand...
I guess I'm at a loss for understanding your point. If there is an SUSE ATS without integral service-side disconnect/ocp, can it actually be installed as service equipment, i.e. be the service disconnect or on line-side of the service disconnect?
 
iwire

iwire

Moderator
Staff member
Location
Massachusetts
Smart $ said:
I guess I'm at a loss for understanding your point. If there is an SUSE ATS without integral service-side disconnect/ocp, can it actually be installed as service equipment, i.e. be the service disconnect or on line-side of the service disconnect?
Click to expand...

Well I guess you are, it seemed very clear to me.

It seems you get lost when no calculations are involved. :D
 
Smart $

Smart $

Esteemed Member
Location
Ohio
iwire said:
Well I guess you are, it seemed very clear to me.

It seems you get lost when no calculations are involved. :D
Click to expand...
Well to be utmost clear, I got your point and stated such with "Quite true..." in response. What I'm not clear on is any beneficial or practical implication, and asked if I am mistaken.

On your closing remark, perhaps to some degree... but to that I say we all have strengths and weaknesses.

Hope you have as great a day as I will... :thumbsup:
 
Status
Not open for further replies.
Top