Is it easier to pull MHF or 4 individual wires?

[tjansson]

I'm going to be burying the feeder for my house, in conduit. Not sure if I should use MHF cable or individual wires.

Here are the specs on the run:

2.5" conduit
60 ft
2x 24" 90 deg sweep
1x 36" 90 deg sweep
200a service, aluminum wire: 4/0 for 2 hots, 2/0 for neutral, 4 for ground

MHF seems like it would be easier to deal with since it's just one spool rather than 4, but maybe a harder pull due the twisted construction.

Should I use MHF cable or individual XHHW wires? Is one much more difficult to pull than the other?

 

[Bretny]

Itsnt MHF direct burrial wire? Why bother with the conduit. By the time you need to pull a new wire in the coduit is going to be junk too.

 

[tjansson]

Itsnt MHF direct burrial wire? Why bother with the conduit. By the time you need to pull a new wire in the coduit is going to be junk too.

Direct burial is a very bad idea in my rocky soil and 48" frost depth.

MHF is rated for direct burial but is ok to use in conduit. I think...

 

[larry4406]

Based on advise here, I decided to pull 4 XHHW wires in 2" conduit vs MHF to my barn. The advice given me was that the XHHW would pull easier due to its slicker insulation. It pulled pretty easy but I had help.

Also I am not a sparky but I think MHF is limited to 90A?? If true, that might not be good for a house.

 

[tjansson]

Also I am not a sparky but I think MHF is limited to 90A?? If true, that might not be good for a house.

I'm not a sparky either but from what I've put together 4/0-4/0-2/0-4 MHF should be good for a 200a subpanel. Not sure why they would make it that big if it wasn't...

 

[wyliesdiesels]

Itsnt MHF direct burrial wire? Why bother with the conduit. By the time you need to pull a new wire in the conduit is going to be junk too.

yes MHF IS direct bury.

Why bother with conduit? Because its cheap insurance and makes it easier to change the wire if needed. Also protects the wire from rocks.

Why would the conduit be junk? That makes no sense...

Based on advise here, I decided to pull 4 XHHW wires in 2" conduit vs MHF to be barn. The advice given me was that the XHHW would pull easier due to its slicker insulation. It pulled pretty easy but I had help.

Also I am not a sparky but I think MHF is limited to 90A?? If true, that might not be good for a house.

Youre not thinking about how MHF comes in several different gauges and the size the OP is using.

#2 AL MHF is limited to 90a for subpanels.

The OP does not have #2 AL. they have 4/0. Much much bigger than #2

I'm not a sparky either but from what I've put together 4/0-4/0-2/0-4 MHF should be good for a 200a subpanel. Not sure why they would make it that big if it wasn't...

4/0 is rated for 180a for a subpanel, not 200a.

check the ampacity table

http://www.barr-thorp.com/wp-content/uploads/2011/04/Digest-176-NEC-Tables.pdf

 

[Innovate1]

I'm not a sparky either but from what I've put together 4/0-4/0-2/0-4 MHF should be good for a 200a subpanel. Not sure why they would make it that big if it wasn't...

You are right at least generally speaking. Not sure what current 4/0 is good for but MHF comes in various sizes. A very common one here is 2-2-2-4 which is good for 90A for a subpanel feed, which, again, is what is commonly discussed here. But that's not the only size.

I am watching this thread because I have the same basic question and think you got the trade offs right. Only other variable I can think of is how slick the insulation is. I plan to use conduit also.

My pricing shows I can buy the single wires in the same size in aluminum for about what MHF would cost. So it basically comes down to pulling and handling ease.

 

[Innovate1]

Itsnt MHF direct burrial wire? Why bother with the conduit. By the time you need to pull a new wire in the coduit is going to be junk too.

By the time it is junk it will be someone else's problem as that will be a long time.

 

[tjansson]

yes MHF IS direct bury

4/0 is rated for 180a for a subpanel, not 200a.

check the ampacity table

http://www.barr-thorp.com/wp-content/uploads/2011/04/Digest-176-NEC-Tables.pdf

Thanks for your input. Why do you say it's only good for 180a? The MHF i'm looking at has 90 deg C USE-2/RHH/RHW-2 insulation, which is rated for 200a on the chart you linked.

 

[teamextreme]

Thanks for your input. Why do you say it's only good for 180a? The MHF i'm looking at has 90 deg C USE-2/RHH/RHW-2 insulation, which is rated for 200a on the chart you linked.

Because you can't use the 90 deg C column, that is only for de-rating calcs. You have to use the 75 deg C column. The wire is rated at 90 deg C, but connections at the breaker are only rated 75 deg C, so everything defaults to that lowest value.

And to answer your original question; it will be much easier to pull individual conductors than a cable.

 

[tjansson]

Because you can't use the 90 deg C column, that is only for de-rating calcs. You have to use the 75 deg C column. The wire is rated at 90 deg C, but connections at the breaker are only rated 75 deg C, so everything defaults to that lowest value.

And to answer your original question; it will be much easier to pull individual conductors than a cable.

Thanks for the info!

By "sub-panel", I mean my house main panel. The meter is getting put on a pedestal with 200a disconnect, and will be feeding the house main panel. The neutral and ground will be bonded at the pedestal and un-bonded at my house main panel. The conduit run I am referring to is between the pedestal and my house main panel. Do I still need to follow the 75 deg column?

I am just confused, because the electrician said we'd use 4/0, and the state utility manual specifies 4/0 for the service feed. I don't see how the service feed is any different from the feeder between the breaker at the meter and the breaker at my "main" "subpanel".

Why aren't I asking my aforementioned electrician? Well, he seems to have fallen off the face of the earth, and I am trying to get moving on this while I find another one...

Thanks for the input, everyone.

 

[Innovate1]

Thanks for the info!

By "sub-panel", I mean my house main panel. The meter is getting put on a pedestal with 200a disconnect, and will be feeding the house main panel. The neutral and ground will be bonded at the pedestal and un-bonded at my house main panel. The conduit run I am referring to is between the pedestal and my house main panel. Do I still need to follow the 75 deg column?

I am just confused, because the electrician said we'd use 4/0, and the state utility manual specifies 4/0 for the service feed. I don't see how the service feed is any different from the feeder between the breaker at the meter and the breaker at my "main" "subpanel".

Why aren't I asking my aforementioned electrician? Well, he seems to have fallen off the face of the earth, and I am trying to get moving on this while I find another one...

Thanks for the input, everyone.

I am not sure but think it's because the POCO has different guidelines.

 

[Bert_]

4/0 is fine for this situation. Wire for a feeder is never required to be larger than wire for the entire service. In this case it sounds like it also carries the entire load for the house. That makes twice that the NEC says it's okay.

Also since there are no 180 amp breakers you can put 4/0 on a 200-amp breaker as long as the load is below 180A

 

[jim111]

OP to answer your original question, MHF 4/0 cable can be pulled in 2.5 inch conduit without a lot of difficulty

 

[Bretny]

Im also at 48in frost depth and my 100a is running through my driveway. You should have seen the basket ball size rocks i had to pull out. I back filled at first by hand.

 

[tjansson]

I ended up using XHHW, individual conductors. I was getting lazy so I made a quick, but bulky "pulling head" and covered with tape. We just lubed the first foot, so it would be easier for the person feeding to wrangle the conductors off of 4 spools and push the wire.

I didn't need a winch or anything, but it took some force to pull/push it through. I blame my quick n dirty pull head.

On the same day i pulled some 4/0-4/0-2/0 triplex through 30 ft of 2.5" with 2x 90 deg 24" radius elbows. Half hitched and taped up the end, lubed the first foot. That pulled very easily.

 

[Fasthotrod]

4/0 is fine for this situation. Wire for a feeder is never required to be larger than wire for the entire service. In this case it sounds like it also carries the entire load for the house. That makes twice that the NEC says it's okay.

Also since there are no 180 amp breakers you can put 4/0 on a 200-amp breaker as long as the load is below 180A

Right on the money, Bert!

More info here: https://iaeimagazine.org/magazine/2013/05/16/whats-happening-to-table-310-15b7/

From the article:

"For example, if you have a 200-amp service fed by 4/0 AWG aluminum conductors and two 200-amp subpanels, the conductors to the subpanels will not be required to be larger than 4/0 AWG aluminum, unless there are temperature correction or adjustment factors that must be applied to the feeders. This is logical since there is no way the load on an individual subpanel feed can be greater than the load on the service conductors."

Hope this helps.

Mark