How deep and ??

[budco]

I am ready to start wiring my shop. The electrician ran AWG 2-2-2-4 aluminum wire from the main panel to a junction box at the back of the house. I have to run about 40' more wire to the panel I'm going to install in the shop. From what I have read I can use a 90 amp breaker at the main panel and a 100 amp at the panel in the shop. Please correct me if this in wrong. What I'd also like to know is how deep I need to bury the cable and the size of the conduit I need to put it in (metal or plastic) ?
thx.

 

[MrBalll]

Look up your local codes to see if they say anything.
Most of the time you need at least 18" below ground minimum.

 

[ddawg16]

As noted above.

In addition....since you are digging a trench....might as well make a bit wider and install a spare conduit for data

And on the conduit...what ever the wire requires...up it once size. The cost difference is minimal.

 

[Falcon67]

18" is typical, 2" will make for an easier pull. Use sweep 90s or you'll have to thread it first then bury it.

You breaker the head end (main panel) at 90A, the shop panel can have anything, whatever comes with the panel (100A is pretty typical). It'll be a disconnect more than any kind of overload protection.

 

[teamextreme]

Use PVC. I don't have any direct experience pulling the MHF cable you are using, but everyone here always recommends 2". The breaker sizes you mentioned are correct. Burial depth for PVC is 18" to the top of the conduit.

 

[justsam]

Have you determined what type of wire or cable you are going to run from the junction box to your shop? Must be capable of 90 Amps.

 

[CNGsaves]

What LENGTH of wire (inside house . . . you say AWG 2-2-2-4 Al) did the electrician run from main panel to junction box where you'll tie in the buried run over to detached garage ??

GJ Sparky's can give you voltage drop once they know entire length of wire end-to-end. Best wire likely will be MHF 2-2-2-4 Al that you'll put in conduit the whole way to detached garage subpanel. Sparky's will give more details once you fill in the gaps.

+1 to dig trench deeper (like 24" to 30") and put electrical 2" conduit at bottom in sand. After all inspections done on electrical, put in 12" backfill dirt and put in 1" conduit for low-voltage like CATV, internet, phone, security, etc.

Recommend you make a scale drawing on grid paper where your trench will be and keep copies at all electrical panels. You will want to know later, and future homeowners will absolutely love your forward thinking !!

 

[wyliesdiesels]

I am ready to start wiring my shop. The electrician ran AWG 2-2-2-4 aluminum wire from the main panel to a junction box at the back of the house. I have to run about 40' more wire to the panel I'm going to install in the shop. From what I have read I can use a 90 amp breaker at the main panel and a 100 amp at the panel in the shop. Please correct me if this in wrong. What I'd also like to know is how deep I need to bury the cable and the size of the conduit I need to put it in (metal or plastic) ?
thx.

Trench needs to be 18" deep to top of conduit.

Table 300.5 gives needed depths.

http://www.xwalk.com/images/Table_300.5-Min_Cover_Reqts.pdf

2" PVC is recommended.

Use #2 AL MHF which can be direct buried but needs to be in conduit where exposed above ground and inside structures. Conduit recommended for entire length.

As others have said, u should bury a few more conduits(1") above the electrical for such things as voice, data, and cable TV....

 

[budco]

What LENGTH of wire (inside house . . . you say AWG 2-2-2-4 Al) did the electrician run from main panel to junction box where you'll tie in the buried run over to detached garage ??

GJ Sparky's can give you voltage drop once they know entire length of wire end-to-end. Best wire likely will be MHF 2-2-2-4 Al that you'll put in conduit the whole way to detached garage subpanel. Sparky's will give more details once you fill in the gaps.

+1 to dig trench deeper (like 24" to 30") and put electrical 2" conduit at bottom in sand. After all inspections done on electrical, put in 12" backfill dirt and put in 1" conduit for low-voltage like CATV, internet, phone, security, etc.

Recommend you make a scale drawing on grid paper where your trench will be and keep copies at all electrical panels. You will want to know later, and future homeowners will absolutely love your forward thinking !!

The length of the cable from the house panel to the junction box is approx 35 feet. It's another I'm guessing 40' to the inside panel. I'm running a compressor 30 back from the panel and then a 220 line to the lift aprox 35' from the panel.

 

[brownbagg]

on conduit, if you can afford it, run three inch, i pulled four wires in 2 inch 100 feet with soap and it was a beech

 

[budco]

Wylie, I sent you a pm but was having problems with my laptop,don't know if you got it or maybe it get sent twice.
thx. Bud

Trench needs to be 24" deep to top of conduit.

Table 300.5 gives needed depths.

http://www.xwalk.com/images/Table_300.5-Min_Cover_Reqts.pdf

2" PVC is recommended.

Use #2 AL MHF which can be direct buried but needs to be in conduit where exposed above ground and inside structures. Conduit recommended for entire length.

As others have said, u should bury a few more conduits(1") above the electrical for such things as voice, data, and cable TV....

 

[pattenp]

Typically, direct bury is 24 inches of cover and PVC conduit is 18 inches of cover. This changes where under streets and driveways, etc., etc.

 

[zmaxmotorsports]

It depends on whether any finish grading is going to be done out there.
A skid loader bucket can turn 18" of dirt into 10" of dirt really fast.

 

[budco]

The wire is running from the house to the shop thru the yard. There won't be anything else done there except maybe some landscaping.

 

[Norcal]

The wire is running from the house to the shop thru the yard. There won't be anything else done there except maybe some landscaping.

If any part is subject to vehicular traffic then 24" of cover is required, otherwise 18".

 

[teamextreme]

Burial depth for PVC is 18" to the top of the conduit.

Trench needs to be 24" deep to top of conduit.

Table 300.5 gives needed depths.

http://www.xwalk.com/images/Table_300.5-Min_Cover_Reqts.pdf

If any part is subject to vehicular traffic then 24" of cover is required, otherwise 18".

wylies, you are always spot on with advice, but I have to question the 24" reference. How do you figure this?

 

[wyliesdiesels]

wylies, you are always spot on with advice, but I have to question the 24" reference. How do you figure this?

Because I was very tired and wasnt paying attention. Disregard...