What's the best way to do this job?

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Coppersmith

Coppersmith

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Location
Tampa, FL, USA
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Electrical Contractor
I'm estimating a job where I come out of the panel in a house, go through the attic, come out the side of the house, go underground for 20 feet, come up outside a detached garage, go through the wall and terminate at a subpanel. Customer has requested 100 amps. Please double check my thinking here.

Aluminum would be a lot cheaper than copper so I should avoid copper solutions.

I can't use SER cable because it's not allowed underground either direct buried or in conduit.

I can't use SEU cable because it's not allowed in the attic due to it not being fire rated.

Seems like the least expensive way would be 3 x AL #1 XHHW and #6 CU ground in conduit from end to end. I'll use EMT in the attic and on the outside walls. I'll use IMC for the underground which means it only has to be buried 6". I'll run the IMC out of the ground and up the wall about 18" for physical protection from lawn mowers then change over to EMT. I can't use PVC in the attic due to it's 122 degree temperature limitation.

Do you see any code violations in my proposed solution? Anybody got a less expensive way to do this?

Here's another way that I don't think will fly with the HO, but I'm curious if it's code complaint: Run a messenger cable between the buildings and use SER cable the entire way. The SER will be attached to the messenger with UV resistant zip ties. I believe SER can be exposed to weather and sunlight. Compliant?
 
Why can't you use SE cable in the attic?

From Southwire:

Applications
Southwire Type SE, service entrance cable is used to convey power from the service drop to the meter base and from the meter base to the distribution panelboard; however, it may be used in all applications where Type SE cable is permitted. SE may be used in wet or dry above ground locations at temperatures not to exceed 90° C. The voltage rating is 600 volts.
Click to expand...

https://www.southwire.com/products/Aluminum-SE-Cable.htm
 
infinity said:
Why can't you use SE cable in the attic?
Click to expand...

I said SEU. I meant USE.

Coppersmith said:
I can't use SER cable because it's not allowed underground either direct buried or in conduit.
Click to expand...

Thanks for the info. I didn't think SER was wet rated. Since it is, looks like I can run SER the entire way. I would have to sleeve it in conduit where exposed and underground. I don't believe it is allowed to be direct buried.
 
1st off, OH usually works out substaintailly less than UG Copperdude

You could theroetically do the entire job in SE, and messenger support OH wiring (art 396)

I'm unsure about this SE 'fire rating' in attics, perhaps 338.10 (B)(4)(a) applies (Uses Permitted)

2nd, if UG is desired, go pvc ,faster, cheaper

~RJ~
 
romex jockey said:
2nd, if UG is desired, go pvc ,faster, cheaper
Click to expand...

The reason I like to use IMC for underground is that I hand dig these trenches and digging down for 18" cover takes substantially longer then digging down for 6" cover. When I compare the labor and material costs, 6"/IMC comes out cheaper than 18"/PVC. Now if I had a 1st year apprentice on staff, that calculation would change.
 
hbiss said:
Rob was just talking generically since SE is the same as SER as far as being allowed to be run in the attic.

-Hal
Click to expand...

Yes, that is what I meant. The OP implied that it wasn't permitted in attics but then amended his respond to say that he was actually referring to USE not SE cable.
 
Coppersmith said:
The reason I like to use IMC for underground is that I hand dig these trenches and digging down for 18" cover takes substantially longer then digging down for 6" cover. When I compare the labor and material costs, 6"/IMC comes out cheaper than 18"/PVC. Now if I had a 1st year apprentice on staff, that calculation would change.
Click to expand...


THAT i hear Copper, myself i hate to dig , done far too much in my time

~RJ~
 
Coppersmith said:
The Southwire link that Infinity showed says their SER is wet-rated. At least I hope it is, I just sold the job.
Click to expand...
338.12(A) Uses Not Permitted (for Service Entrance Cable)
(2) Underground with or without raceway.

As the conductors inside SER are labeled XHHW (to my knowledge), does that mean one could strip the sheath off the underground portion and be compliant?

Cheers, Wayne
 
infinity said:
https://www.southwire.com/products/Aluminum-SE-Cable.htm
Click to expand...

So I went to buy SER cable today hoping it was wet-rated like the Southwire SER that Infinity liked above. The cut sheet

https://www.encorewire.com/wp-content/uploads/EncoreWire_ALCAT_SER.pdf

is confusing because it says wet but also says for above ground applications. The print on the cable jacket itself says:

"ENCORE WIRE CORP TYPE SE STYLE R THHN OR THWN AA-8000 AL CDRS 600 VOLTS (NO. OF CDRS)(SIZE) + 1 CDR (SIZE) (UL) DATE/TIME/OPER/QC"

The cut sheet also says the conductors are THWN or XHHW.

So is this cable able to be used in underground conduit?
 
Coppersmith said:
So I went to buy SER cable today hoping it was wet-rated like the Southwire SER that Infinity liked above. The cut sheet

https://www.encorewire.com/wp-content/uploads/EncoreWire_ALCAT_SER.pdf

is confusing because it says wet but also says for above ground applications. The print on the cable jacket itself says:

"ENCORE WIRE CORP TYPE SE STYLE R THHN OR THWN AA-8000 AL CDRS 600 VOLTS (NO. OF CDRS)(SIZE) + 1 CDR (SIZE) (UL) DATE/TIME/OPER/QC"

The cut sheet also says the conductors are THWN or XHHW.

So is this cable able to be used in underground conduit?
Click to expand...

SE cable is not permitted underground in conduit regardless of the insulation type within the cable.

338.12 Uses Not Permitted.
(A) Service-Entrance Cable. Service-entrance cable (SE)
shall not be used under the following conditions or in the
following locations:
(1) Where subject to physical damage unless protected in
accordance with 230.50(B)
(2) Underground with or without a raceway
Click to expand...
 
I just inspected the cable and found that the internal conductors are marked THWN (except the bare obviously). Since they are marked, does that mean I can strip the outer jacket at the point where I transition to outside (there is an LB there) and be compliant? I think I'm allowed to run a bare AL ground.
 
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