Hello guys, couple electrical questions on our new 24'x50' detached shop we are building: we are installing a Siemens 100 amp panel and the power will be coming from my house panel (200 amp) that is 150' away. I am planning on using aluminum 4 wire and running conduit but i need to know what size and type of wire? Also, how deep do i need to trench the conduit? Let me know if you need more info. Thanks for the help! Tracy
New shop build - couple questions
- Thread starter Rebird
- Start date
pattenp
Well-known member
If you want the full 100A for a feeder you need three #1 Al conductors and one #6 Al for the equipment ground. Direct bury is 24" of cover, PVC conduit is 18" of cover. Please note.. wire that is direct bury that is only rated USE-2 is not to enter a structure, it has to be terminated outside. If using direct bury look for a rating of USE-2/RHH/RHW-2 which can enter the structure. All direct bury wire needs to be in conduit where above ground and inside the structure. If using conduit panel to panel I suggest using Al XHHW-2 with 2" conduit. If any part of the run that's inside and conduit is not possible then use a large junction box and transition to SER Al 1-1-1-3 cable. Wire size and depth is per the NEC, local requirement may differ.
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rburke65
Well-known member
Spend the extra dollar and run an additional pvc conduit ....or 2. Inexpensive insurance my friend.
Can someone let me know if the attached would work for my needs? BTW, my run is actually 180' (not 150'). Thanks!
https://www.wireandcableyourway.com/2-0-2-0-1-4-aluminum-mobile-home-feeder-cable.html
https://www.wireandcableyourway.com/2-0-2-0-1-4-aluminum-mobile-home-feeder-cable.html
75gmck25
Well-known member
Considering the length of the cable run, that's probably a good choice if you want 100 amps. Many folks use dual rated 2-2-2-4 AL MHF because its less expensive and easy to find in stock, although its only rated for 90 amps.
I ran 2" for the electrical conduit and IIRC I used 1.5" for the low voltage conduit. It took a fair amount of lubricant and pulling to get 2-2-2-4 MHF through 2" 90 degree long sweep bends, but it was simple through the straight section. My wire was dual rated for inside use and burial (I think the wire in your link is also), so I could run it in conduit right into my subpanel.
The four MHF wires came bundled, with a piece of fiberglass tape every few feet to keep them together. Keep track of the junctions in your conduit, and pull the wire in a direction that does not catch on the lip where the conduit is glued together. That lip looks really small, but does a good job of catching the tape around the individual wires. Make sure you include a new pull string in both conduits, so you can go back later if needed.
Bruce
I ran 2" for the electrical conduit and IIRC I used 1.5" for the low voltage conduit. It took a fair amount of lubricant and pulling to get 2-2-2-4 MHF through 2" 90 degree long sweep bends, but it was simple through the straight section. My wire was dual rated for inside use and burial (I think the wire in your link is also), so I could run it in conduit right into my subpanel.
The four MHF wires came bundled, with a piece of fiberglass tape every few feet to keep them together. Keep track of the junctions in your conduit, and pull the wire in a direction that does not catch on the lip where the conduit is glued together. That lip looks really small, but does a good job of catching the tape around the individual wires. Make sure you include a new pull string in both conduits, so you can go back later if needed.
Bruce
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Ok, i ran my all my MHF (2/0, 2/0, 1 and 4) in conduit and now i need to go into the interior of my shop. As i understand it, the MHF must be in conduit in the interior as well. This is some pretty thick cable so would it be easier to terminate in an exterior junction box and just run the appropriate sized copper cable into my interior 100 amp panel? Also, what is the appropriate sized copper cable? If a junction box is acceptable, what type of connectors do i use to connect AL to Copper? Thanks for all the help! T
pattenp
Well-known member
I've run #2 MHF many times in 2" conduit inside to panels and have never had to switch to a different cable. Either run straight into back of the panel from the exterior wall if panel is on exterior wall using a LB, or use a couple of LB's back to back for pull/turn points to get into panel. Or use a piece of PVC flex conduit.
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Hopefully my last question..... I am receiving power from my 200 amp house panel..... but the 2/0 hot wires are much larger in diameter than my 100 amp breaker in my house panel will allow to connect. What is my best option? Thanks for the help!
pattenp
Well-known member
I'm so sorry, I misread your post on the wire size. I thought you ran #2 MHF, but you said #2/0. What brand breaker panel do you have? 100A breakers will usually take up to a #2/0. If yours doesn't you will need to splice on a smaller short piece to fit the breaker. The breaker should have stamped on it the max wire size. Do not trim down the conductor to fit.
Edit: For the short splice piece you can go down to #1 Al. The splice can be made in the main panel.
Edit: For the short splice piece you can go down to #1 Al. The splice can be made in the main panel.
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pattenp
Well-known member
Polaris is easiest but most expensive. Lowes and Home Depot carry Splice Reducers or Split Bolts and are the cheapest route but need to be taped up well.