MHF or URD

[chevytrucks84]

just finished hanging the steel and now time for the electric. I have a 230 ft run from the house the the barn (36×48). I have been trying to find 2/0 mhf but it's all special order at 500ft. I can get urd by the foot. The guy at the supply house says if urd stays in conduit it can enter the building. I am under 2009 code and it would be inside for 6 ft inside of 2 1/2" conduit.

 

[wyliesdiesels]

just finished hanging the steel and now time for the electric. I have a 230 ft run from the house the the barn (36×48). I have been trying to find 2/0 mhf but it's all special order at 500ft. I can get urd by the foot. The guy at the supply house says if urd stays in conduit it can enter the building. I am under 2009 code and it would be inside for 6 ft inside of 2 1/2" conduit.

The guy at the supply house didnt know what he was talking about. URD CANNOT enter the structure no matter if its in conduit or not. This is due to the insulation rating not being fire resistant.

What u could do is URD on the outside then transition to another wire type such as SER for the interior portion.

BTW, NEC years are every 3 so 2014 2011 2008 2005....u must be on 2008...

What size service do u plan on having in the garage?

 

[Marcm157]

The guy at the supply house didn't know what he was talking about. URD CANNOT enter the structure no matter if its in conduit or not. This is due to the insulation rating not being fire resistant.

Can URD be brought directly into the sub panel from the outside through an LB? Don't want to hijack the thread but that is what I am about to do (tomorrow actually) with the electric on my build.

 

[wyliesdiesels]

Its not suppose to be inside structures period!

 

[Marcm157]

Its not suppose to be inside structures period!

Thank You!

 

[chevytrucks84]

I want 100 amps in the shed. Possibly a welding machine shop big air compressor. I may have a 2nd service installed some day.

My neighbor just had his barn built and wired I checked with his sparky and he has 2 2 2 1 urd to his in conduit in the buildings and inspector said good to go.

Point me to where I can get 250 ft mhf I'll do it. I'm not in a huge hurry for it and I'm not sure about getting it from the eBay sellers

 

[Marcm157]

This is where I got my cable from. Great people to deal with, decent prices, very helpful and free shipping.

http://www.nassauelectrical.com/

 

[theoldwizard1]

Even if you are planning on having every machine in your shop running at the same time you are never going to hit 100A !

Get a realistic power estimate. You may only need 2-2-2-4 MHF.

FYI - MHF must be in conduit when above ground.

 

[pattenp]

NEC is explicit that USE only rated wire is to be terminated outside of the structure.

 

[chevytrucks84]

Your looking at 50amp at 245 ft with 3%. I'd rather go big now and not have to worry or have problems. Back feeding with a whole house generator at the barn may not work with that

I was looking at the Nassau electric site but no price for mhf I'll have to call. The Syracuse urd is use-2 rated if that means anything.

 

[Marcm157]

Your looking at 50amp at 245 ft with 3%. I'd rather go big now and not have to worry or have problems. Back feeding with a whole house generator at the barn may not work with that

I was looking at the Nassau electric site but no price for mhf I'll have to call. The Syracuse urd is use-2 rated if that means anything.

Definitely worth a call.

 

[pattenp]

Go to www.wireandcabletogo.com and buy individual wires of aluminum xhhw-2. I assume you are running conduit underground.

 

[chevytrucks84]

Go to www.wireandcabletogo.com and buy individual wires of aluminum xhhw-2. I assume you are running conduit underground.

I would rather not run conduit. The xhhw-2 would be for conduit? What would work for direct bury?

 

[chevytrucks84]

Thanks all for being adamant with the mhf and not using urd. Why would I hear I could "use" urd for this application when it is against code.

 

[pattenp]

Use XLP/USE-2/RHH/RHW-2. Wireandcabletogo has it and it is direct bury and can go inside in conduit.

 

[wyliesdiesels]

I want 100 amps in the shed. Possibly a welding machine shop big air compressor. I may have a 2nd service installed some day.

My neighbor just had his barn built and wired I checked with his sparky and he has 2 2 2 1 urd to his in conduit in the buildings and inspector said good to go.

Point me to where I can get 250 ft mhf I'll do it. I'm not in a huge hurry for it and I'm not sure about getting it from the eBay sellers

First of all people confuse insulation and cable types all the time. Are you sure it was URD?

Second inspectors miss things all the time. I wouldn't put it past them. Who knows the inspector might've not even looked at the feeder cables.

I would rather not run conduit. The xhhw-2 would be for conduit? What would work for direct bury?

If you don't want to run conduit inside the building your only option is a jacketed type cable such as SER. Any type of individual conductors without an outer jacket needs to be in conduit when inside, that includes XHHW, MHF etc.

However SER cannot go underground. So you would have to use an underground direct bury rated cable and then transition in junction boxes on the outside to SER.

Thanks all for being adamant with the mhf and not using urd. Why would I hear I could "use" urd for this application when it is against code.

Simple. Because people don't know all the codes.

 

[pattenp]

Thanks all for being adamant with the mhf and not using urd. Why would I hear I could "use" urd for this application when it is against code.

The thing is there is some URD cable , or at least it's referred to as URD that has the RHH/RHW-2 rating in addition to USE-2 and that makes it okay to be inside. Typical URD or sometimes called secondary underground power distribution cable is only USE-2 rated. Also the conductors on URD are marked only as multiple phase conductors plus one neutral conductor, there is no identified grounding conductor.

 

[theoldwizard1]

The thing is there is some URD cable , or at least it's referred to as URD that has the RHH/RHW-2 rating in addition to USE-2 and that makes it okay to be inside. Typical URD or sometimes called secondary underground power distribution cable is only USE-2 rated. Also the conductors on URD are marked only as multiple phase conductors plus one neutral conductor, there is no identified grounding conductor.

I don't know how you professionals keep this stuff straight ! All multi-conductor cable is made up of multiple single conductors (Duh !).

Southwire mobile home feeder consists of four quadruplexed type RHH or RHW-2 or USE-2

But if URD is USE-2 rated, why can't it be run in a conduit above ground like MHF ?


Anytime I try to learn more about these type of questions I usually give up. The only thing I do find is that MHF seems to be the "best bang for the buck" when wiring up a detached building from an existing structure with a load center that can accept a 90A breaker !

Sparkys correct me if I am wrong, if you absolutely have to go more than 90A to your other structure, you are going to need a meter base with dual lugs OR an outdoor disconnect right off the meter.

 

[theoldwizard1]

FYI :

Menards has 2-2-2-4 MHF $1.62/foot in stores. You can order a 500' spool with free store delivery for $716 or $1.42/foot.

Home Depot has 500' spool of 2-2-2-4 MHF delivered to a store for $699.

 

[theoldwizard1]

Go to www.wireandcabletogo.com and buy individual wires of aluminum xhhw-2. I assume you are running conduit underground.

They also have MHF but with shipping it is $$$ !

 

[wyliesdiesels]

I don't know how you professionals keep this stuff straight ! All multi-conductor cable is made up of multiple single conductors (Duh !).

But if URD is USE-2 rated, why can't it be run in a conduit above ground like MHF?

What u missed or skipped over in what pattenp said was the word PHASE. He was talking about the markings on each individual conductor. If u go back and read what he wrote I bet you will get it.

URD can be ran above ground in conduit. Just not inside.

MHF has a triple rating- USE-2, RHH, RHW

Anytime I try to learn more about these type of questions I usually give up. The only thing I do find is that MHF seems to be the "best bang for the buck" when wiring up a detached building from an existing structure with a load center that can accept a 90A breaker !

Sparkys correct me if I am wrong, if you absolutely have to go more than 90A to your other structure, you are going to need a meter base with dual lugs OR an outdoor disconnect right off the meter.

Thats not necessarily true. It all depends on the loads on the main service panel and the maximum size breaker that the panel can take.

 

[jim111]

I don't know how you professionals keep this stuff straight ! All multi-conductor cable is made up of multiple single conductors (Duh !).

But if URD is USE-2 rated, why can't it be run in a conduit above ground like MHF ?


Anytime I try to learn more about these type of questions I usually give up. The only thing I do find is that MHF seems to be the "best bang for the buck" when wiring up a detached building from an existing structure with a load center that can accept a 90A breaker !

Sparkys correct me if I am wrong, if you absolutely have to go more than 90A to your other structure, you are going to need a meter base with dual lugs OR an outdoor disconnect right off the meter.

You are not limited to a 90 amp breaker to feed a sub-panel out from your existing structure. You just have to use a cable rated to handle the correct amperage and proper installation ratings for your particular application

 

[pattenp]

What u missed or skipped over in what pattenp said was the word PHASE. He was talking about the markings on each individual conductor. If u go back and read what he wrote I bet you will get it.

Thanks Wylie for pointing that out.

theoldwizard1, Not sure about your comment "All multi-conductor cable is made up of multiple single conductors (Duh !)", but yes URD is a multiconductor cable. What I was trying to say was that the conductors in URD are identified as phase conductors and a neutral conductor. Triplex URD is 2 phase conductors and a neutral conductor and Quadruplex URD is 3 phase conductors and a neutral conductor.

 

[CNGsaves]

With the harsh freeze/thaw cycles in Michigan, I'd sure recommend OP go with CONDUIT for the entire buried section. Go with 2" sch 40 for the underground portion and sch 80 above ground where it could get damaged and use 90 sweeps for the transition to above ground.

By using the low cost aluminum MHF, you can afford the conduit !!

While you've got trench open and some backfill, put in another 1" or 1 1/2" conduit for low voltage stuff like internet/CATV/phone/security/etc.

 

[pattenp]

They also have MHF but with shipping it is $$$ !

At wireandcabletogo the 2-2-2-4 MHF is $1.17 a foot, estimate buying 250ft + $54 shipping works out to be $1.38 a foot. That's a good price.

I missed from my previous post that wireandcabletogo had MHF.

Edit: A side note is the picture of the MHF on the wireandcabletogo site is of URD. You'll notice the one conductor with a yellow stripe is the marking of the neutral. MHF will be two blacks, one white, one green.

 

[chevytrucks84]

I think i am Going to go with Nassau electrical.
AL RHH RHW XLP USE. 750ft and a 251 ft