Can You Review the 100 Amp Service For My Pole Barn?

[lakeroadster]

I was hoping some of the electrical guru's here could review what I got quoted for the power running to my soon to be erected pole barn.

They are going to access power via the meter box and run about 100 ft to the barn, trenched underground.

Here's what was quoted:

100 amp
Wire: #2 URLD 4 direct burial self healing, approx. 100 ft
Electrical Panel: Square D Hom24M100C
(1) 20 amp outlet,
(2) -15 amp switches,
porcelain light fixture,
jelly jar light fixture,
2 ground rods.

This will be enough to get me up and running. I'll pull another permit and do all the interior wiring myself once I get the equipment located.

Thanks

_____
John

 

[theoldwizard1]

If you are tapping off of your panel in the house and are willing to use a 90A breaker (everything else stays the same) there you can probably use MHF cable and save a bundle.

 

[wyliesdiesels]

I was hoping some of the electrical guru's here could review what I got quoted for the power running to my soon to be erected pole barn.

They are going to access power via the meter box and run about 100 ft to the barn, trenched underground.

Here's what was quoted:

100 amp
Wire: #2 URLD 4 direct burial self healing, approx. 100 ft
Electrical Panel: Square D Hom24M100C
(1) 20 amp outlet,
(2) -15 amp switches,
porcelain light fixture,
jelly jar light fixture,
2 ground rods.

This will be enough to get me up and running. I'll pull another permit and do all the interior wiring myself once I get the equipment located.

Thanks

_____
John

URD is not permitted to be ran inside.

And #2 AL is only good for 90a in this application.

If you are tapping off of your panel in the house and are willing to use a 90A breaker (everything else stays the same) there you can probably use MHF cable and save a bundle.

Actually URD and MHF are pretty close to the same price....

 

[lakeroadster]

Thanks.

I should have mentioned that the existing meter box panel is mounted outside the home on a metal box, not attached to the home.

So you can't run PVC through the side wall of the barn, run the same PVC into the panel, then run the URD wire into it?

If it is less than 100 ft is the #2 good for 100 amps?

____
John

 

[wyliesdiesels]

Thanks.

I should have mentioned that the existing meter box panel is mounted outside the home on a metal box, not attached to the home.

So you can't run PVC through the side wall of the barn, run the same PVC into the panel, then run the URD wire into it?

If it is less than 100 ft is the #2 good for 100 amps?

____
John

Nope. URD's insulation isnt fire resistant. That doesnt change even if its ran in conduit.

And yes the voltage would be just under 6 volts under max load of 90a which isess than 3%...

 

[theoldwizard1]

So you can't run PVC through the side wall of the barn, run the same PVC into the panel, then run the URD wire into it?

MHF can and must be run in conduit inside buildings.

If you are doing direct burial use a Schedule 80 "sweep" when transitioning from below ground to above ground.

 

[lakeroadster]

I sure get tired of people quoting **** that doesn't meet spec.

As for URD inside, maybe the guy is going to use an LB on the outside of the building, then use service cable into the building?

But why would he quote #2 when I specified 100 amp?

Anything I could be missing before I go back at the guy? Is #2 copper URD available? Would that make a difference?

Again, just trying to get this straight before I contact the contractor.

_____
John

 

[wyliesdiesels]

MHF can and must be run in conduit inside buildings.

If you are doing direct burial use a Schedule 80 "sweep" when transitioning from below ground to above ground.

Wizard- youre not paying attention. URD and MHF are 2 DIFFERENT types of cable.

URD cant be ran inside and MHF can but needs to be in conduit!

I sure get tired of people quoting **** that doesn't meet spec.

As for URD inside, maybe the guy is going to use an LB on the outside of the building, then use service cable into the building?

But why would he quote #2 when I specified 100 amp?

Anything I could be missing before I go back at the guy? Is #2 copper URD available? Would that make a difference?

Again, just trying to get this straight before I contact the contractor.

_____
John

It is possible that the URD is dual rated for RHH/RHW, which is the correct insulation rating for indoors.

So i would ask him what the brand and exact ratings of the cable are.

As far as #2 AL having an ampacity of 100a, that is only allowed when it serves the ENTIRE load of a dwelling.

Since pole barn isnt a dwelling, its max ampacity is 90a.

However, there has been much debate about this an contractor and inspectorsalike get this wrong all the time.

There is even quite a few threads on here where we go into detail about this.

As far as junctioning the URD outside to say SER cable, that is a possibility.

If it were mine, i would use MHF(mobile home feeder)...

 

[theoldwizard1]

Wizard- youre not paying attention. URD and MHF are 2 DIFFERENT types of cable.

URD cant be ran inside and MHF can but needs to be in conduit!

I seems you and I are in violent agreement ! (At least that was what I was trying to say.)

 

[pattenp]

........

As for URD inside, maybe the guy is going to use an LB on the outside of the building, then use service cable into the building?

Anything I could be missing before I go back at the guy? Is #2 copper URD available? Would that make a difference?
_____
John

A 2" LB is not large enough to splice #2 URD to #2 SER. So you better not see any splicing done in the LB.

Also I don't know of any copper URD. For 100A you can use individual #3 Cu THHN/THWN-2 or #1 Al. RHH/RHW-2.

Look at this to see different wire product. http://www.southwire.com/products/ProductCatalog.htm



*

 

[lakeroadster]

Thanks guys... I'll go back to the contractor, let him know what's up and have him get specific in regard to brand, spec., sizes and ratings. I'll also get clarification on how / where he plans to terminate the URD wire outside the structure.

Thanks again.

_____
John

 

[lakeroadster]

I checked with the county inspector, as well as 2 other licensed electricians. They are all in agreement that what was proposed is acceptable as long as the URD is enclosed in conduit when inside the building, up to the panel.
_____
John

 

[pattenp]

I checked with the county inspector, as well as 2 other licensed electricians. They are all in agreement that what was proposed is acceptable as long as the URD is enclosed in conduit when inside the building, up to the panel.
_____
John

Well that flies in the face of the NEC if just USE rated

 

[mikeyc.]

Is the MHF rated for wet location? I'm running mine in conduit under ground then into building and must be rated "W". Thanks

 

[wyliesdiesels]

I checked with the county inspector, as well as 2 other licensed electricians. They are all in agreement that what was proposed is acceptable as long as the URD is enclosed in conduit when inside the building, up to the panel.
_____
John

Thats not to code...

Is the MHF rated for wet location? I'm running mine in conduit under ground then into building and must be rated "W". Thanks

Yes...its direct bury rated but conduit is good insurance...

 

[lakeroadster]

I checked with the county inspector, as well as 2 other licensed electricians. They are all in agreement that what was proposed is acceptable as long as the URD is enclosed in conduit when inside the building, up to the panel.
_____
John

Well that flies in the face of the NEC if just USE rated

Thats not to code...

Do me a favor fellas... point out the specific NEC sections that this violates, and I'll bring it to the attention of the electrician and the inspector.

I want it done right, but if the electrician is saying it meets code, and the inspector says it meets code, my only recourse is to show them the specific code violations.

Thanks,

____
John

 

[pattenp]

Do me a favor fellas... point out the specific NEC sections that this violates, and I'll bring it to the attention of the electrician and the inspector.

I want it done right, but if the electrician is saying it meets code, and the inspector says it meets code, my only recourse is to show them the specific code violations.

Thanks,

____
John

USE only rated cable NEC 338.12 (B) (1) Not in interior, and (2) not used above ground except where enclosed in conduit and terminated outside.

There are some cables called URD that carry the additional rating of RHH/RHW-2 that can go inside. But you need to see the cable and read the markings. If you see only the USE marking then it needs to stay outside by code.

Here's two examples of UD cable that list them as USE.

http://www.encorewire.com/wp-content/uploads/EncoreWire_ALCAT_SR_UD.pdf

http://www.southwire.com/ProductCatalog/XTEInterfaceServlet?contentKey=prodcatsheet40


*

 

[mikeyc.]

Thanks Wylie

 

[lakeroadster]

USE only rated cable NEC 338.12 (B) (1) Not in interior, and (2) not used above ground except where enclosed in conduit and terminated outside.

There are some cables called URD that carry the additional rating of RHH/RHW-2 that can go inside. But you need to see the cable and read the markings. If you see only the USE marking then it needs to stay outside by code.

Here's two examples of UD cable that list them as USE.

http://www.encorewire.com/wp-content/uploads/EncoreWire_ALCAT_SR_UD.pdf

http://www.southwire.com/ProductCatalog/XTEInterfaceServlet?contentKey=prodcatsheet40


*

Excellent Thanks for your help, and thanks to everybody else for their comments and guidance also.

 

[mikeyc.]

Will I be able to run 2-2-2-4 MHF in 2" conduit with one sweep successfully? Or should I use single wires? Also, does it matter what end I start at? The sweep is 5 feet from the end of a 100' run. Thanks

 

[wyliesdiesels]

Yes #2 AL MHF will be fine in 2"...

 

[mikeyc.]

Thanks again. I appreciate it. I'm laying the conduit now and will be wiring my pole barn with 60A service in 100A panel. 130' run. I can still upgrade to 90A service in the future with the 2-2-2-4 if necessary,correct? Thank you.

 

[wyliesdiesels]

Yes. U can change the breaker to 90a....

 

[Shadowdog500]

Have you asked them to quote what it would take to wire the whole building? His crew will be there anyway, and stuff isn't getting any cheaper.

I planned on doing the same as you plan to do, but asked for a quote to do everything. For the additional cost it was worth it. And it was really nice having everything done in two days.

A friend chose to wire an light his own shop 10 years ago, one of these years he will be done. I would have fit it in my other projects and would have taken forever myself.

Chris

 

[lakeroadster]

USE only rated cable NEC 338.12 (B) (1) Not in interior, and (2) not used above ground except where enclosed in conduit and terminated outside.

There are some cables called URD that carry the additional rating of RHH/RHW-2 that can go inside. But you need to see the cable and read the markings. If you see only the USE marking then it needs to stay outside by code.

Here is what is being used. Let me know if you think there is an issue, it's not due to be covered up for 4 days.

The 3 main lead lines are marked:
SOUTHWIRE (UL) AWG 2 8000 AL. --- AlumaFlex 9R0 AA8176 AL TYPE USE-2 OR RHH OR RHW-2 SIS 60 MILS XLP 600 VOLT JAN/05/2016 . #032108MCT

The ground wire is marked:
E32071 (UL) AWG 6 COMPACT AL. --- AlumaFlex (TM) AA8176 TYPE USE-2 OR RHH OR RHW-2 SIS 60 MILS XLP 600 VOLT 2015 . #599340JAR 0735-18

And based on NEC Table 310.16 Ampacities - AWG 2 this wire is ok for 100 amp service, correct?

 

[Norcal]

The wire is not "good for 100 amps" but when it's used according to the rules in the NEC it is allowed to be undersized for a 100A dwelling service, not for subfeeds, pole barns, or other outbuildings.

 

[CNGsaves]

OP . . . . those all individual wires ???

Also, no conduit for the 100 ft buried run . . . . . . right ???

That appears to be very rocky soil . . . . will there be lots of sand in trench ???

 

[lakeroadster]

OP . . . . those all individual wires ???

Also, no conduit for the 100 ft buried run . . . . . . right ???

That appears to be very rocky soil . . . . will there be lots of sand in trench ???

Yes individual strands

Yes no conduit

Per the local county inspector: The way direct burial wire is installed here in the "Rocky Mountains" is the trench is dug, large rocks are removed, bedding material (sand) is placed in the trench, the wire is placed, bedding material is placed on top of the wire, then caution tape is placed on the bedding material, then the trench is filled.

 

[CNGsaves]

^ ^^ Glad to hear you're putting sand in the trench !!

Will you have enough depth in trench to backfill 12" and put in conduit for low voltage like CATV (RG6) and internet/phone/security (CAT5e) ??

Then your caution tape above that ??

 

[lakeroadster]

As far as #2 AL having an ampacity of 100a, that is only allowed when it serves the ENTIRE load of a dwelling.

Since pole barn isn't a dwelling, its max ampacity is 90a.

However, there has been much debate about this an contractor and inspectorsalike get this wrong all the time..

The wire is not "good for 100 amps" but when it's used according to the rules in the NEC it is allowed to be undersized for a 100A dwelling service, not for subfeeds, pole barns, or other outbuildings.

Would someone be so kind as to point out what specific paragraph of the code states the rules in regard to dwelling vs pole barn?

Also, FWIW as previously stated, power is coming from the meter outside the house, not from the panel inside the house.

Thanks,

 

[Norcal]

2011 and back is table 310.16, it was renamed in the 2014 plus the table allowing # 2 AWG AL for a 100A residential service was removed, with that edition you have to do load calc's to be allowed to undersize the conductors. I do not have my code book handy to give further information.

 

[Big Daddy Chop Shop]

Ill be the "outsider" here. Not an electrician, Commercial HVAC technician by trade.

Do I am running power to my building soon, and have done the leg work. This was my experience.

NO supply house or electrician I talked to recommended MHF for this application. Three Commercial electricians, 4 supply houses. Multiple reasons were given, but for me, it is VERY simple. If you go to a real supply house (not Lowes or Home depot) individual feeders are cheaper. I was also brought to my attention that this is the correct way to do it.

And yeah, 2-2-2-4 is rated for 100 amp service as you have stated OP, it is what every single person I spoke with recommended.

I am no expert, but i know several. And I know who to trust and who not to trust. I am in contact with vendors everyday. I know who I can count on, and who I can't. I also have just a smidge (lol) or experience with non buried cable and electrical from my field days.

Bottom line is this. Go to a reputable electrical supply house and check up for yourself. If you need bigger wire they are MORE than happy to sell it to you. If not, a good one will tell you you are throwing cash away. While there, check up on your contractor. Counter guys see the contractors everyday. They have a pretty good idea who knows their **** and who is full of it.

Good luck OP

 

[pattenp]

..........
NO supply house or electrician I talked to recommended MHF for this application.

Good luck OP

I believe this is more so a location issue. The MHF seems to more readily available and used in southern states. The wire (USE-2/RHH/RHW-2) the OP pictured that he has gotten to use is the same type conductors used in MHF. The MHF is just a preassembled cable. Yes you may save a few $ buying the conductors individually.

I've seen people sold the wrong wire from so called reputable electrical supply houses.

 

[laser3kw]

100' foot run between buildings? 100' of cable seems a little short. You can easily burn 20' on each end going inside the structure to the termination.

 

[lakeroadster]

2011 and back is table 310.16, it was renamed in the 2014 plus the table allowing # 2 AWG AL for a 100A residential service was removed, with that edition you have to do load calc's to be allowed to undersize the conductors. I do not have my code book handy to give further information.

Thanks.

As a retired Mech Engr I've spent most of my career saying "Here is the applicable ASME code paragraph." or "What is the applicable ASME code paragraph?" But since we are dealing with the NEC I am "out of my wheel house".

Since I am reading that Table 310.16 isn't applicable if someone would be so kind as to point out what specific paragraph of the NEC does apply that would be most excellent.

.... And yeah, 2-2-2-4 is rated for 100 amp service as you have stated OP, it is what every single person I spoke with recommended......

Good luck OP

Thanks. The folks at the county and the electric guy I am using are saying I'm good for 100 Amps. But that is flying in the face of the guru's here on the GJ.

I'd just like to run through the NEC specific paragraphs, for my own "enlightenment" to be sure it is done "per code".

... I've seen people sold the wrong wire from so called reputable electrical supply houses....

That's my fear in this case. I am not at all worried that the #2 aluminum won't handle the 100 amps, I just want to be sure what is being used meets "code".

100' foot run between buildings? 100' of cable seems a little short. You can easily burn 20' on each end going inside the structure to the termination.

Actual run from meter to panel is 118 ft.
__________________________________________

I really appreciate every members input on this thread.

 

[pattenp]

.........

Since I am reading that Table 310.16 isn't applicable if someone would be so kind as to point out what specific paragraph of the NEC does apply that would be most excellent.

NEC 225 covers feeders run between buildings. 225.5 states table 310.15 (2011 NEC) is to be used.

So as a feeder you do use the table 310.15(B)(16) you posted above. Use the 75 deg.C columin and you'll see 100A is #3 Cu or #1 Al. The equipment ground needs to be #8 Cu or #6 Al per Table 250.122

Also look at table 310.104(A) Conductor Applications - wire that has insulation listed as "Flame retardant" can be installed inside. You'll see that USE/USE-2 does not have that listing so it needs to stay outside. See 338.12(B) for where USE only rated conductors may not be installed.

 

[lakeroadster]

NEC 225 covers feeders run between buildings.

Thanks.

In my case it runs from the meter box, located in the front yard, to the pole building. Does that matter?

 

[pattenp]

Thanks.

In my case it runs from the meter box, located in the front yard, to the pole building. Does that matter?

I don't believe so.

 

[klassenl]

I want it done right, but if the electrician is saying it meets code, and the inspector says it meets code, my only recourse is to show them the specific code violations.
____
John

If your electrician and your local inspector say its correct you're very...um... bold in trying to prove them wrong. Especially when you don't know the code.

 

[wyliesdiesels]

Here is a photo of what is being used. Let me know if you think there is an issue, it's not due to be covered up for 4 days.

The 3 main lead lines are marked:
SOUTHWIRE (UL) AWG 2 8000 AL. --- AlumaFlex 9R0 AA8176 AL TYPE USE-2 OR RHH OR RHW-2 SIS 60 MILS XLP 600 VOLT JAN/05/2016 . #032108MCT

The ground wire is marked:
E32071 (UL) AWG 6 COMPACT AL. --- AlumaFlex (TM) AA8176 TYPE USE-2 OR RHH OR RHW-2 SIS 60 MILS XLP 600 VOLT 2015 . #599340JAR 0735-18

And based on NEC Table 310.16 Ampacities - AWG 2 this wire is ok for 100 amp service, correct?

310.16 is the old chart. 310.15(b)(16) is the new one.

The 90* c column is for derating purposes only. There are no termination points(ie breaker lugs) that are rated for 90* c.

So #2 al is good for 90a.

There is an exception(that i believe was removed) that allowed #2 al to be used at 100a when feeding a dwelling.

2011 and back is table 310.16, it was renamed in the 2014 plus the table allowing # 2 AWG AL for a 100A residential service was removed, with that edition you have to do load calc's to be allowed to undersize the conductors. I do not have my code book handy to give further information.

310.15(b)(16) started in 2011 NEC code cycle