Wiring to new garage under deck

[bradpac]

I have decided that 100 amps should be fine for my garage and that my 200 amp house service should be fine with this additional load. So, now I need to run the wire and get it inspected. My plan is to use gray PVC conduit with MHF wire inside. I have about 10 feet of open yard to go across, so there, I can bury it 18" deep. But after that I have about 20 feet of wood deck that's a few inches off the ground and right next to the house that I have to run under. What is the proper way to run the wire here? The deck is 20x20, I can pull up some boards, but I don't want to move the whole thing to bury wire underneath it. You guys have helped me get this far, just need a little more help to finish it off.

Attached a simple diagram to aid in understanding my rambling.

 

[andyvh1959]

Assuming your location, your house is either on a slab or over a crawlspace, correct? If you can route the new service under the house to the side near the garage, then you only have to bury the conduit/cable from there to the garage. If that is not an option then perhaps conduit under the deck until you get to the area where the conduit/cable must be buried.

A deck is a temporary structure, even if attached to the house. Conduit under the deck provides cable protection even if the deck was not there. But I'm sure many persons here well versed in the NEC have the best replies.

 

[pattenp]

The conduit can be strapped to the bottom of the deck but must be buried where not covered by structure. I assume you're using #2MHF which is good for up to 90A, not 100A. If the exposed conduit is subject to damage it needs to be sch80.

 

[bradpac]

The conduit can be strapped to the bottom of the deck but must be buried where not covered by structure. I assume you're using #2MHF which is good for up to 90A, not 100A. If the exposed conduit is subject to damage it needs to be sch80.

Strapped to the bottom of the deck, that is what I'm looking for. Is it allowed for me to go from galvanized conduit to PVC. I was thinking using galvanized where it's exposed might be a tougher option.

On the wire size, I was actually thinking of going bigger, with such a short run cost isn't too big of factor on the wire.

 

[bradpac]

Assuming your location, your house is either on a slab or over a crawlspace, correct? If you can route the new service under the house to the side near the garage, then you only have to bury the conduit/cable from there to the garage.

It is slab, but in this soil we have fairly deep beams along the perimeter, not sure what this house is but can be as deep as 36" depending on how the engineering came out. My garage has 30" deep beams with a 6" slab. Lots of concrete on black dirt expansive clay soil.
But going under the slab is not an option. Sounds like strapping it to the deck is going to be the solution.

 

[pattenp]

Strapped to the bottom of the deck, that is what I'm looking for. Is it allowed for me to go from galvanized conduit to PVC. I was thinking using galvanized where it's exposed might be a tougher option.

On the wire size, I was actually thinking of going bigger, with such a short run cost isn't too big of factor on the wire.

You can transition from pvc to metal but sch80 pvc is tough if you want the added protection and will be easier to work with.