Wiring through Service Disconnects
Wiring through Service Disconnects
(OP)
The photos listed below show service disconnects that a subcontractor has installed to bring power to a newly installed boiler (15 million BTU's) in a boiler plant.
They originally had one line coming to one service disconnect and then to the boiler panel and supplying power to 3 contactors (burner motor-air compressor and oil pump motor).. jumpering from contactor to contactor. This was worng according to the manufacturers installation instructions, which mandates a seperate service disconnect for each unit.
To rectify this, they have left that main feed line in place at the service disconnect, installed two more service disconnects next to it, and on the line side, jumpered from service disconnect #1 to #2,.. then from #2 to #3.
(see photo below)
Is this allowable by code? I have searched through NEC 2002 but have not found anything that may address it.
Thank you for any assistance..
Tom Fitzgerald
Savannah, Ga.
Also
They originally had one line coming to one service disconnect and then to the boiler panel and supplying power to 3 contactors (burner motor-air compressor and oil pump motor).. jumpering from contactor to contactor. This was worng according to the manufacturers installation instructions, which mandates a seperate service disconnect for each unit.
To rectify this, they have left that main feed line in place at the service disconnect, installed two more service disconnects next to it, and on the line side, jumpered from service disconnect #1 to #2,.. then from #2 to #3.
(see photo below)
Is this allowable by code? I have searched through NEC 2002 but have not found anything that may address it.
Thank you for any assistance..
Tom Fitzgerald
Savannah, Ga.
Also






RE: Wiring through Service Disconnects
The load side of the two service disconnects that were added were then brought back through the first disconnect and out to the boiler panel..
Thanks for any input...
Tom
RE: Wiring through Service Disconnects
Lugs must be listed for the number/size of conductors installed.
Enclosure must provide sufficient bending space for the size/quantity of wires installed.
Conductor must be protected by upstream overcurrent protective device or fall under appropriate tap rule conditions.
I don't believe that the jumpering on the line side of the disconnects is, in and of itself, a Code violation.
However, wiring a load side conductor through a foreign disconnect enclosure would be a violation unless there is adequate space in the enclosure. See 312.8.
RE: Wiring through Service Disconnects
What is the purpose of the unfused disconnect switch?
Lugs must be listed for the number/size of conductors installed, cannot put 2 conductors under same screw. See UL White Book and Article 110.
Carries grounding conductors for branch circuits, but I did not see grounding conductor from main feeder.
A wireway above the switches would make the problems go away.
RE: Wiring through Service Disconnects
RE: Wiring through Service Disconnects
Second issue is using the boxes as a wireway, clearly an NEC violation. The SqD switches have such small boxes that there is no room for the additional cable fill. If you have them correct it with square duct make sure they follow the wire fill guidelines on it.
RE: Wiring through Service Disconnects
RE: Wiring through Service Disconnects
The setup for existing boilers have the MCC on the other side of the plant (not within view).. They brought one line from the MCC to the new boiler (rather than 3 lines) and have stated that according to NEC, the disconnets have to be close by within sight. They said the first switch is unfused because that main line is already fused at the MMC..
Tom..
RE: Wiring through Service Disconnects
PLease let me know
David wilson
Strategies Inc
wilson@strategiesmarketinginc.com
RE: Wiring through Service Disconnects
An existing 600A disconnect with parallel 350MCM per phase in 3-1/2" conduits that leaves the bottom of the disconnect and goes underground immediately. The disconnect is surrounded by other service equipment (multiple services) and there is not much room.
An ASCO automatic transfer switch was added to this feeder. The contractor mounted the switch nearby on a new concrete pad. To get from the disconnect to the ASCO switch and back the contractor installed 8" wireway and 3-1/2" conduits. That part looks fine. Inside the disconnect however you have parallel 350MCM leaving the load side of the disconnect going out the side of the disconnect through 2- 3-1/2" chases then you also have the same parallel 350MCM's coming back from the ASCO switch through 2 more 3-1/2" chases. Then splices were made to the underground feeder in the disconnect. So in the disconnect you have a big pile of splices and wire, but it is the same feeder, not a foreign one. The contractor used Burndy Unitaps which helped some if you've ever seen them.
Outage time was a concern, I think, since the service is for a call center type business.
Could this be a code violation?
RE: Wiring through Service Disconnects
This is a code violation as enclosures cannot be used as a raceway. Enclosures are typically sized to accomadate wire in and out of the device. In addition, the splice within the enclosure is a potential for a fault, which could damage you service entrance disconnect, even though the Burndy Unitaps are a good product for connection of multiple connections. It appears to me that either a lager wire trough or a properly sized junction box should be used for the splice of the load side of the ATS conductors.
RE: Wiring through Service Disconnects
Please cite the code section. Thanks.
Don
RE: Wiring through Service Disconnects
312.8 Enclosures for Switches or Overcurrent Devices.
Enclosures for switches or overcurrent devices shall not be used as junction boxes, auxiliary gutters, or raceways for conductors feeding through or tapping off to other switches or overcurrent devices, unless adequate space for this purpose is provided. The conductors shall not fill the wiring space at any cross section to more than 40 percent of the cross-sectional area of the space, and the conductors, splices, and taps shall not fill the wiring space at any cross section to more than 75 percent of the cross-sectional area of that space.
RE: Wiring through Service Disconnects
See Article 404.3 (B).
RE: Wiring through Service Disconnects
RE: Wiring through Service Disconnects
As long as you feel OK with the installation and it passed inspection, I guess the case is closed.
RE: Wiring through Service Disconnects
Personally I was not satisfied with it, but I passed on the info to the PE who runs the job and he was satisfied with it, the owner (the Army) was satisfied with it, and the people who run the plant were satisfied with it so.. (Shrug)... as long as I have my comments on record (in RMS, if it comes back to bite anyone later, it won't be me!
Being I'm an old Navy man working for the Army, I make waves from time to time. (but don't capsize the boat)..
Thanks again.....
Tom
RE: Wiring through Service Disconnects
Agreed. There’s many a slip ’twixt the cup and the lip.
As long as you feel OK with the installation and it passed inspection, I guess the case is closed. [/quote]
Being primarily a contractor.......that sounds good to me.
Btw, TomFitz, didn't mean to be rude by interjecting on your thread here. I thought it was dead and since it was on a very similar subject....
RE: Wiring through Service Disconnects
RE: Wiring through Service Disconnects
Cheesy wiring indeed.
Real amateur work. Was the Inspector blindfolded when he came by?
Code violations aside. How does one easily modify or remove any one disconnect?
A D box and some 1/2" sealtite flex would have been much easier. Probably faster install as well.
Oh well everyone is an Apprentice at one time.