SER to MHF via Terminal Block

[bucktim]

Hello,

I've read a bunch of posts on this topic, but haven't seen a lot of answers on what to use for the wire transition.
I want to run SER AL 2-2-2-4 in my basement to an outside junction box, then switch to MHF AL 2-2-2-4. To make the transition inside the junction box (plastic 12x12x6) I want to use Marathon 1414300, 4 pole, 2-14awg terminal block. The block is rated at 115V, 600A.
Just wanted to verify this is an acceptable way to transition for a 100Amp service?
Also seems to be very economical, ~$25.

Thanks

 

[mm08822]

The block is rated for 115a, 600v. It will be adequate for a 100a feeder.
You dont specifically state, but I assume you are running a feeder to a dettached garage. #2 Al is only good for 90a in that case. 100a rated panel with 100a main cb is ok in garage. Need a 90a cb in house panel.

Consider conduit point to point with xhhw conductors instead. That can eliminate jboxes and 2 sets of connections that dont add any value. Just the the potential for failure sometime in the future. Certainly more time and material for the install.

What is the overall feeder length?
What are the loads? Simultaneous loads? How did you arrive 90/100a?

 

[bucktim]

You are exactly correct, my plan was to use 90A in house and 100A on sub panel in detached garage.
The run length is ~75 from house to outside wall, then ~35 to sub panel.
The plan for the garage is automotive hobby mainly. It would have 220v for a air compressor (5hp), 2post lift and maybe a welder in the future, currently I only have a 120v welder.
This would be pretty low volume, only as a hobby, so I don't see much risk in me tripping any breakers. It would be rare that any of the major current draw items would be run at the same time.

As for the xhhw, I haven't really read much on it. I would rather avoid running conduit though the basement, but its not out of the question. The basement is finished, so I will be dropping the some ceiling tiles, though some area's would be a bit more difficult if I was trying to add conduit.

 

[bucktim]

I have done some reading on the XHHW. Looks like homedepot has 500ft for $151. I could use that to make my 4 wires and run in 2" Schedule 80 all the way. The price wouldn't be too much different when all done.

Would that still be 90A at the house breaker?

 

[wyliesdiesels]

I have done some reading on the XHHW. Looks like homedepot has 500ft for $151. I could use that to make my 4 wires and run in 2" Schedule 80 all the way. The price wouldn't be too much different when all done.

Would that still be 90A at the house breaker?

You didnt specify the gauge of the xhhw.

But if its #2 then the answer is yes it would need to be protected with 90a breaker at the house.

Also your compressor will need to be hardwired- nema outlet wont work. A disconnect is required as well, if not within sight of and further than 50’ from, the breaker panel.

 

[bucktim]

Yes the XHHW would be 2 gauge. I will keep the main breaker at 90amp then.
The plan would be to have the air compressor hardwired and within 50' of break sub panel, so I think we are okay there.

Are there any issues with using the same 2 gauge wire as the ground wire also?
I just see on the HD product page, someone is saying to run #6. Also 2-2-2-4 is #4 for ground...

 

[mike93lx]

Yes the XHHW would be 2 gauge. I will keep the main breaker at 90amp then.
The plan would be to have the air compressor hardwired and within 50' of break sub panel, so I think we are okay there.

Are there any issues with using the same 2 gauge wire as the ground wire also?
I just see on the HD product page, someone is saying to run #6. Also 2-2-2-4 is #4 for ground...

Bigger is not a problem

 

[wyliesdiesels]

Yes the XHHW would be 2 gauge. I will keep the main breaker at 90amp then.
The plan would be to have the air compressor hardwired and within 50' of break sub panel, so I think we are okay there.

Are there any issues with using the same 2 gauge wire as the ground wire also?
I just see on the HD product page, someone is saying to run #6. Also 2-2-2-4 is #4 for ground...

The only issue you may run into is the size of the lug on the groundbar.

#2 may not fit in it.

 

[mm08822]

Unless you are getting a break on the full spool pricing, I would suggest 2-2-4-4 or 2-2-4-6 xhhw. (#6 in green.)

You use 1.5" PVC or even 1.25". 2" is overkill.

 

[bucktim]

I assume XHHN is a typo? Doesn't come up in google.

I guess I have decided to run the conduit the full length: house breaker, through basement then underground to the sub panel.

That means I should be able to use this cable: 2-2-4-6 MHF, 100A, "Aluminum Mobile Home Feeder cable has a type USE2/RHH/RHW-2 cross linked polyethylene (XLP) insulation" @ only $1.06 per foot?

I would definitely have issues trying to get #2 to fit the ground lugs and 1.5"PVC.

 

[mm08822]

I would use individual xhhw conductors and not mhf. individual conductors (straight, no twist) will pull easier.

 

[pattenp]

2-2-4-6 MHF is to be protected at 90A when used as a branch feeder, not 100A. MHF is direct bury and is harder to work with in conduit than XHHW.

 

[bucktim]

Coming full circle
XHHW @ 2-2-4-6 seems like the way to go.
Easier to pull, and can order individual wires, so ends up cheaper.

Thanks for everyone's help.

 

[wyliesdiesels]

dont forget to isolate the neutral bar(s).

 

[bucktim]

dont forget to isolate the neutral bar(s).

Yep, I read that from some other posts.

Thanks

 

[pattenp]

Back in post #4 you said sch80 conduit. Sch40 is okay if not subject to being damage.

 

[bucktim]

Back in post #4 you said sch80 conduit. Sch40 is okay if not subject to being damage.

Funny you say that, today I was doing some reading on 80 vs 40 and came to the same conclusion.

Thanks