osmrsparks
New User
- Location
- Washington
- Occupation
- Electrician
I'm a huge fan of the Mike Holt forum. I've found many a good advice here over the years. After ready through a few forum posts here, I think I found the answers I need, but decided to join and post here to confirm.
I am located in rural Washington state with my electrical work inspected by Washington State Labor & Industries inspectors (but they don't like to answer questions). I just installed a new 200 Amp Square D QO CU816F200PS meter/disconnect combo (CSED) surface mounted to the exterior of an out building that didn't previously have power. It was 250 horizontal feet (not including risers) from the pole to the building. I installed 3" Sch 40 conduit, discontinuous as required by the poco (Puget Sound Energy). The poco pulled 4/0 to the meter. I was a bit surprised they didn't use 250 KCMIL for that distance and 200 A. Anyway, that isn't my question (though I am curious to know what others think about that). The CSED has a 200 Amp disconnect, space for 8 breakers, and feed thru lugs at the bottom of the bus bars. I plan to use some of the 8 breaker spaces to supply circuits to the outbuilding that the CSED is attached to (building A), and I plan to use the feed thru lugs to feed a panel in a separate out building (building B). The outbuildings are too far away from the residence to connect from there.
My question is about the conductor and conduit sizes to use to connect the Feed Thru Lugs on the CSED (on outbuilding A) to a 125 Amp Square D QO main circuit breaker (MCB) surface mounted on the interior of an exterior wall of outbuilding B). The distance between buildings is 180 feet. It is a straight shot so no bends in the conduit are required other than a 90 at each end rise up. I plan to install continuous schedule 40 conduit. The conduit will enter the bottom of the CSED outdoors on building A and ideally (if allowed) would enter the back of the MCB using an LB on the exterior of the building. If LB isn't allowed there, then I would need to drill through the slab in the floor and come up into the bottom of the MCB.
My understanding is that I would need to either use 200 Amp size conductors (since I'm NOT feeding from a breaker in the CSED, just the 200 Amp disconnect protected service bus feed thru lugs), which I think would need to be 4/0-4/0-2/0-4 like the 4/0 conductors feeding the CSED, and and minimum schedule 40 conduti size would be 2.5 inch conduit (but I'd probably use 3.0 inch), or I could treat it as a tap (entirely outdoor so no limit to distance) and reduce the conductor size to 125 Amp size protected only by the 125 Amp main breaker in the panel in outbuilding B. Am I correct in determining that in this case, the minimum conductor size would be 2/0-2/0-1-4 MHF or XHHW and minimum schedule 40 conduit size would be 2 inch (but I'll probably use 2.5 inch)?
I am located in rural Washington state with my electrical work inspected by Washington State Labor & Industries inspectors (but they don't like to answer questions). I just installed a new 200 Amp Square D QO CU816F200PS meter/disconnect combo (CSED) surface mounted to the exterior of an out building that didn't previously have power. It was 250 horizontal feet (not including risers) from the pole to the building. I installed 3" Sch 40 conduit, discontinuous as required by the poco (Puget Sound Energy). The poco pulled 4/0 to the meter. I was a bit surprised they didn't use 250 KCMIL for that distance and 200 A. Anyway, that isn't my question (though I am curious to know what others think about that). The CSED has a 200 Amp disconnect, space for 8 breakers, and feed thru lugs at the bottom of the bus bars. I plan to use some of the 8 breaker spaces to supply circuits to the outbuilding that the CSED is attached to (building A), and I plan to use the feed thru lugs to feed a panel in a separate out building (building B). The outbuildings are too far away from the residence to connect from there.
My question is about the conductor and conduit sizes to use to connect the Feed Thru Lugs on the CSED (on outbuilding A) to a 125 Amp Square D QO main circuit breaker (MCB) surface mounted on the interior of an exterior wall of outbuilding B). The distance between buildings is 180 feet. It is a straight shot so no bends in the conduit are required other than a 90 at each end rise up. I plan to install continuous schedule 40 conduit. The conduit will enter the bottom of the CSED outdoors on building A and ideally (if allowed) would enter the back of the MCB using an LB on the exterior of the building. If LB isn't allowed there, then I would need to drill through the slab in the floor and come up into the bottom of the MCB.
My understanding is that I would need to either use 200 Amp size conductors (since I'm NOT feeding from a breaker in the CSED, just the 200 Amp disconnect protected service bus feed thru lugs), which I think would need to be 4/0-4/0-2/0-4 like the 4/0 conductors feeding the CSED, and and minimum schedule 40 conduti size would be 2.5 inch conduit (but I'd probably use 3.0 inch), or I could treat it as a tap (entirely outdoor so no limit to distance) and reduce the conductor size to 125 Amp size protected only by the 125 Amp main breaker in the panel in outbuilding B. Am I correct in determining that in this case, the minimum conductor size would be 2/0-2/0-1-4 MHF or XHHW and minimum schedule 40 conduit size would be 2 inch (but I'll probably use 2.5 inch)?
