New build in progress...need electrical help!

[aka Larry]

Ok so my new shop build is progress and I have a few questions. The questions are mostly electrical stuff for now, but more to come later as I progress. The shop will be a 40’x40’ metal framed building with three roll-up doors and one personnel door. The slab is done and the building should be erected in about 2 weeks.

So here are my plans. Feel free to comment or ask questions. I’m not an expert but I have stayed a Holiday Inn Express once.

Electrical Feed:

Distance: 210’ +/-
Service Size: 100A (split off 200A service incoming to house)
Feeder Wire: Aluminum 2-2-2-4 MF encased in 1-1/2” PVC conduit…just to be safe

The plan is to dig the trench myself and lay the conduit with the MF wire stubbed up *near* the meter and inside the shop. I will hire an electrician to hook-up the main feed to both panels and I’ll do the rest of the wiring inside the building. I’ve already had the existing utilities located so I’m about ready to get started.

My questions are as follows, and try be nice if I ask any stupid questions, because I’m learning some of this as I go.

1. Can I run a phone line and water in the same trench since the MF wire will be in conduit?
2. Does the phone line even need to be in conduit? If so can it be inside the same one as the MF wire?
3. How do you feed such a big-*** wire like the MF through the conduit for that distance?

So now I anxiously await to hear from the wisdom of my fellow GJ members…

 

[Speedy Petey]

A few questions first:
What is MF wire?
How do you propose to "split off" the house service? You CANNOT simply connect it in the meter pan. You must come off a breaker in the main panel.

NO, phone wire CANNOT be in the same conduit as the feeder wire.
Yes, you can share the trench. Depending on where you are the water will need to be MUCH deeper than the electric.

 

[aka Larry]

A few questions first:
What is MF wire?

Oops, should have said "MHF" (mobile home feeder) wire.

How do you propose to "split off" the house service? You CANNOT simply connect it in the meter pan. You must come off a breaker in the main panel.

Again, I used the wrong terminolgy used to describe it generically. I have room in the main panel for another breaker which will supply power to the shop. This is the part the electrician will handle.

NO, phone wire CANNOT be in the same conduit as the feeder wire.
Yes, you can share the trench. Depending on where you are the water will need to be MUCH deeper than the electric.

Thanks. I'm not 100% sure on whether or not I'm even going to run water at this time, but I do need a phone line since my wireless security system won't span that distance. I'll need to add another keypad in the shop, thus the phone line requirement.

 

[nehog]

There are minimum separation distances for power vs. 'communications' wires. They are covered in the NEC codes for example. IIRC, it (separation) is six inches. Cable designed for direct can be buried without conduit, but I recommend conduit as it protects the wires better from minor gardening accidents.

FWIW, I use a 12 inch wide trench, and put power on one side, and phone (class 2) on the other side, giving about eight inches between them. In most cases I go with 2" conduit.

 

[Friartuck]

100 Amp service is rather generous. Do you need 100A?? Would think 60A at 220 would meet most needs. Work with the electrician now before you start, he may have an issue or a suggestion that may save time, $$, etc.

Consider for future uses:

1. Run a 1/2 or 3/4 inch PVC line for your water. I believe BOCA/NEC has it as it must be one foot seperation from the electric and make it deeper than the electric,

2. Run a 3/4 or one inch PVC conduit for misc. stuff like low voltage electric (phone, intercom to house, cable TV, Computer Ethernet cable, alarm/security). I also ran a small air line in this conduit as my compressor is in the garage, but bead blaster is in the basement

 

[Coolerman]

Figure what you need now then run an extra conduit!

When I planned my shop I planned for a 1 1/4" for a power feed from the house panel, a 1 1/4" for a water line (used this to pull 1/2" Pex through), and a 1" for "other stuff". I figured that was plenty, I was wrong...

My electrician had a brain fart when installing the under ground feeder from the pole to the basement for the main power feed to the house. He was supposed to also run two 1" conduits in the same trench. One for phone and one for cable/satellite. Well since the house being built was 42 miles from the house we were living in, I could not be there every day to supervise. I didn't realize he had not done this until I called the phone company to have a line installed and the tech called me from the site wanting to know how he was supposed to get the line to the house! That's when I was like, "Oh ****!"

I ended up using the spare 1" conduit between the shop and house to get phone, Satellite TV, Satellite Internet, and alarm back to the house then back to the shop. You couldn't pull a piece of string in that conduit right now! So always run an extra conduit or two, you never know what the future will bring...

 

[Charles (in GA)]

Electrical Feed:
Distance: 210’ +/-
Service Size: 100A (split off 200A service incoming to house)
Feeder Wire: Aluminum 2-2-2-4 MF encased in 1-1/2” PVC conduit…just to be safe

Well, you might think you are going to have 100 amp, but #2 Al is only good for, depending on the installation, 90 amps at best, according to NEC. The only way NEC allows 100 amp with #2 AL is when it is used as a residential service, to a dwelling, which this is not.

How do you propose to "split off" the house service? You CANNOT simply connect it in the meter pan. You must come off a breaker in the main panel.

Well, he could if the meter were designed to be "double tapped" (two sets of lugs for each connection) but....... he did answer that it will be supplied off the main panel, so the point is moot. (Very few 200 amp meter sockets are designed with two sets of lugs)

Charles

 

[pattenp]

I highly recommend that you use 2" PVC conduit. It will make the pulling of the wire easier, especially with the 210' run. You will need someone pushing as you are pulling.

Edit: FYI - Use Sch40 PVC underground and Sch80 PVC when above ground and exposed to possible damage.

 

[Falcon67]

>3. How do you feed such a big-*** wire like the MF through the conduit for that distance?

You use 2" conduit and lay a big pull rope in it when you run it. 3/8" or 1/2" nylon sounds good from here. Get a bottle of wire lube at Lowes or HD. Tie the wire securely to the pull rope, grease the wire up good going into the pipe and have a person feeding and one pulling. It'll be a job. My run was 36'. 210' - that'll be somewhat more effort.

When you lay the conduit, pay attention to the swedge joints so that you don't hit pipe edges when you pull.

Same for your phone - use at least a 1" pipe and pull a new pull string in with the phone cable. you may want to add something in there later.

 

[Charles (in GA)]

Yes, turn the bellmouths on the leading end of the pipe so the wire won't be hanging on the sharp edges. Also, take the time to round the inside edges of the pipe ends with a pocket knife so there won't be any sharp edges.

I have some flat braided/woven rope/strap that was made for Bell Systems for pulling thru conduits. It is rated at 1800 lbs. Some people use an ATV to do the pulling, depending on how the wire exits the pipe.

Charles

 

[coolreed]

Use copper conductors not aluminum. Run the conductors (4 wire, color coded)
in a proper grounded conduit. Run your 'shielded' phone line in a separate grounded conduit at least a foot from the power conduit.

Tap off your house panel with the appropriate breaker to the panel in the shed.
Properly ground your shed panel.

My best advice would be either to read up on the NEC and follow it or have a licensed electrician perform the installation of the panels. It is not difficult just follow the rules. Otherwise you are taking a risk.

Good Luck

 

[VHF]

Copper is significantly more expensive. For 210' it would probably cost almost $1000 *more* to run #2 CU than #2 AL.

While copper might be "better", AL is certainly code compliant, and a lot more budget friendly.

I would recommend running a 1" conduit for phone/network/alarm/etc. Keep it at least 6" away from the main power conduit. If doing a narrow trench with a trencher, you could bury your main power conduit, backfill 6" to 12", then drop in the 1" low voltage conduit.

Don't forget to bury a red "buried wire" caution tape when back filling. Typically backfill half, lay the tape, backfill the rest.

NEC requires the top of the power conduit to be 18" below grade; 24" where it goes under a driveway. I don't think there is a depth requirement for low voltage communications lines.

I'm planning to use 1.5" conduit with 2-2-2-4 AL for my 125' run, but I haven't done it yet so I don't know how difficult the pull will be. I already have 1.5" stubbed up through my garage slab, so it's too late for me to upsize to 2" conduit. Some people recommend usinig 2" to make the pull easier, but several folks with experiance have said the 1.5" will be OK.

 

[Charles (in GA)]

NEC requires the top of the power conduit to be 18" below grade; 24" where it goes under a driveway. I don't think there is a depth requirement for low voltage communications lines.

This may be incorrect depending on your interpretation of Table 300.5. One and two family dwelling driveways have an 18" depth specified either for direct burial or metal/non-metalic raceways.

I know it says "and used only for Dwelling related purposes" but I think the intent is to distinguish from "streets, highways, roads, alleys, driveways and parking lots" that sets a 24" depth. I think the latter is in reference to non-residential, public use.

In any case, the best thing to do is go 24" for all of it, and you will never have a problem. Low voltage, under 30 volt, has different requirements, and for communications circuits, you would need to consult the appropriate codes.

Charles