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minimum breaker size for use with MHF wire?

ixlr8

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Joined
Sep 15, 2009
Messages
441
Location
Eastern Shore Virginia
I want to run 2-2-2-4 MHF wire from my house to feed the 100amp panel in my shop. I am going to upgrade the 200amp breaker panel in my house in the in the spring, but I need to run the wire now. It is a FPE panel in the house and I can't get new breakers for it. I know it is a fire waiting to happen, that is why I am changing it. The largest breaker I have available is a 30 amp, that is all I will need for now. Will the MHF wire fit the 30 amp breaker? If not, is there anything that I can do to get something to work until I upgrade the box when I can put in a 70 amp breaker for the shop?
Thank you,
 
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unsinkable

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Feb 23, 2014
Messages
57
Location
New England
I strongly recommend against making ANY taps or adds to that "fire pacific" panel.
Those breakers RARELY trip when needed, you are adding additional paths for additional problems.
I realize you're thinking it's "wire for wire", but a number 2 will let alot more current to keep flowing in the event that the number 10 doesn't burn up.

Most service upgrades I get called for that have FPE panels, never tripped, usually an overloaded branch ckt lights a device on fire and prompts the call.
Change it all out as soon as possible.
Good luck !
 
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ixlr8

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Joined
Sep 15, 2009
Messages
441
Location
Eastern Shore Virginia
Thank you for the recommendations. After further research on FPE panel issues, I am going to see if I can get my panel upgraded sooner than current plans. I can say that I am not happy that the home inspector didn't mention these issues with FPE panels when I bought the house!! Presently I have 8-10 inches of snow on the ground. If the ground is too frozen to bury the MHF cable, can I just lay it on the ground until the ground thaws, do I need to put it in conduit? I know I probably should put it in conduit just to protect it, but is it required?

Thank you
 

toplessHO

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Oct 20, 2014
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14,151
Location
central florida
there are replacement breakers for FPE panels that do work.
both the 2 pole breaker shown have UL listings
that said I would do this only as a temporary method.
 

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ishiboo

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Oct 27, 2010
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9,481
Location
Oshkosh, WI
Thank you for the recommendations. After further research on FPE panel issues, I am going to see if I can get my panel upgraded sooner than current plans. I can say that I am not happy that the home inspector didn't mention these issues with FPE panels when I bought the house!! Presently I have 8-10 inches of snow on the ground. If the ground is too frozen to bury the MHF cable, can I just lay it on the ground until the ground thaws, do I need to put it in conduit? I know I probably should put it in conduit just to protect it, but is it required?

Thank you

Depends on your definition of "can't". You can't legally do either thing. If you're going to do it temporarily, I would use conduit and make sure it can't be driven over.
 

CNGsaves

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Sep 26, 2012
Messages
13,233
Location
KS and OK
Ground isn't frozen so snow won't stop progress. Go for it !! :D

I'd recommend burying conduit anyway as it's your best long-term solution . . . 2" Sch 40 while underground, then Sch 80 once above ground. Make sure it's meets minimum depth required in your local area.

Make sure you call Dig-Safe to mark all underground utilities before doing any digging. Good luck.

While you have trench dug, you might consider putting in another conduit at less depth for stuff like internet, CATV, security (CAT5e/6 ; RG6 ; spare CAT5e). See if local code allows shared trench.
 
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ixlr8

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Sep 15, 2009
Messages
441
Location
Eastern Shore Virginia
I am not sure if the ground is frozen or not, it has been below freezing a few nights before the snow arrived. Local code pretty much does not exist so I can do what I want. Only the folks with waterfront property are held to any sort of code. Our local CEO is a joke, he works for 3 different towns, if 6 people ask him how to do something, they will get 7 different answers. Which is why I am asking for best practice recommendations. Dig-Safe has been called in the past with all lines marked so I know where they are, nothing in the area I am going to be running the cable. All lawn between house and shop so no driving in that area. I planned on burying cable in conduit and I planned on a second 1-1/2" conduit for other stuff. Maybe some 3/4" well pipe to get water out to the shop in the same trench. What is the minimum recommended distance between power conduit and the 'other stuff' conduit? If my foggy memory serves me, other threads here have recommended at least 12". I think frost line here is about 4 ft, I am assuming I need to put the conduits in below that.
Thank you again,
 
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ixlr8

Well-known member
Joined
Sep 15, 2009
Messages
441
Location
Eastern Shore Virginia
there are replacement breakers for FPE panels that do work.
both the 2 pole breaker shown have UL listings
that said I would do this only as a temporary method.

I have never seen those, where would I find them? I will only go this route if I can't get the panel changed out sooner than in the spring.
 
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