Help with MHF 100 amp panel

[stroked89coupe]

I have no idea what I am doing and may pay an electrician to do the job. I would like to learn how to do this the right way. I know the very basics of electric. Wether I do the job or not, if i can learn anything then it will be worth the little effort I put forth.


I want to run mhf 100 feet to my new garage. I have a 200 amp panel with quite a few breakers free. I want around 100 amp service in the shop. I want to put the mhf in 2'' conduit and continue the conduit inside the shop and the house to the actual panels. I think this is the correct way to do this because the mhf does is not allowed indoors except if it is in conduit.


What size wire do i need and how do Iigo about hooking this up. Thanks for the help.

 

[69gp]

I have no idea what I am doing and may pay an electrician to do the job. I would like to learn how to do this the right way. I know the very basics of electric. Wether I do the job or not, if i can learn anything then it will be worth the little effort I put forth.


I want to run mhf 100 feet to my new garage. I have a 200 amp panel with quite a few breakers free. I want around 100 amp service in the shop. I want to put the mhf in 2'' conduit and continue the conduit inside the shop and the house to the actual panels. I think this is the correct way to do this because the mhf does is not allowed indoors except if it is in conduit.


What size wire do i need and how do Iigo about hooking this up. Thanks for the help.

What is it that you are calling mhf? for that run you are probably looking at using #1 XHHW aluminum wire.

 

[stroked89coupe]

Mobile home feeder wire. I know I need something along the lines of 2-2-2-6. But I'm not 100 percent sure.

 

[ishiboo]

Mobile home feeder wire. I know I need something along the lines of 2-2-2-6. But I'm not 100 percent sure.

2-2-2-4 would not be good for 100A on a sub panel. It is sufficient for supplying 100A service though, one of the interesting things about the NEC. So, you may need to install a 75A or 90A breaker (depending on cost/availability) if it is inspected.

If it is difficult to install a conduit, you could transition in a junction box to SER and run it in the house/shop if the installation permits. If it's a simple straight run, you can definitely go all the way in with MHF and conduit.

 

[stroked89coupe]

2-2-2-4 would not be good for 100A on a sub panel. It is sufficient for supplying 100A service though, one of the interesting things about the NEC. So, you may need to install a 75A or 90A breaker (depending on cost/availability) if it is inspected.

If it is difficult to install a conduit, you could transition in a junction box to SER and run it in the house/shop if the installation permits. If it's a simple straight run, you can definitely go all the way in with MHF and conduit.

When you say 75 or 90 amp breaker, do you mean the main breaker?


I would be ok with 90 amp. Would 2-2-2-4 be a good choice ran in conduit inside and out?

 

[Bib Overalls]

You didn't say how far your garage is from your house. Lets say less than 100 feet total run/panel to panel.

2-2-2-4 will get you 90 amps in the shop.

You will need to lay out the run from panel to panel. If your house panel is on an exterior wall you may be able to run your conduit through the wall and down into the ground. The same at the garage. If the panel is not on an exterior wall things get complicated.

If your house has crawl space you can go down from the panel and then out under the footing or through the foundation stem wall. If your house is on a slab you can go up into the attic and then out to the eave and then down into the ground.

Conduit is not required for the horizontal run underground but many electricians recommend it, particularly in rocky soil.

Hooking up at the panels is fairly basic. You will have two conductors that run from the circuit breaker in the house to the panel in the garage. A third conductor, the neutral, which is marked with a white stripe, runs from the neutral buss in the house panel to the neutral buss in the garage. You may need a larger lug to connect to the house buss bar but the lug on the garage panel should accept the neutral conductor. The smaller, bare aluminum conductor is the ground and it runs from the ground buss bar in the house to the ground buss bar in the garage. If you feel uncomfortable making these connections, by all means, hire an electrician.

If you can dig the trench and run the conduit you will save big bucks. Electricians charge the same hourly rate for digging as they do for working with wire.

Making the connection at the house panel and bringing the cable to the exterior is going to be the hardest part of this job. If you have trouble figuring how to do it get back to us with some photos and drawings.

This advice is most likely to late for you but I recommend a "Combo" meter base for almost all new home construction or when the service is upgraded. A combo meter base has three sections, the meter base at the top, a circuit breaker type disconnect in the middle (sometimes called a fireman's switch), and, at the bottom, four to eight circuit breaker positions. With this base, adding future circuits for a new garage, swimming pool, or other purpose is much simplified. A combo base costs about $100-120. In some cases, swapping the old meter base for a combo is simpler and more cost effective than tunneling through wall to reach the existing service panel.

 

[stroked89coupe]

You didn't say how far your garage is from your house. Lets say less than 100 feet total run/panel to panel.

2-2-2-4 will get you 90 amps in the shop.

You will need to lay out the run from panel to panel. If your house panel is on an exterior wall you may be able to run your conduit through the wall and down into the ground. The same at the garage. If the panel is not on an exterior wall things get complicated.

If your house has crawl space you can go down from the panel and then out under the footing or through the foundation stem wall. If your house is on a slab you can go up into the attic and then out to the eave and then down into the ground.

Conduit is not required for the horizontal run underground but many electricians recommend it, particularly in rocky soil.

Hooking up at the panels is fairly basic. You will have two conductors that run from the circuit breaker in the house to the panel in the garage. A third conductor, the neutral, which is marked with a white stripe, runs from the neutral buss in the house panel to the neutral buss in the garage. You may need a larger lug to connect to the house buss bar but the lug on the garage panel should accept the neutral conductor. The smaller, bare aluminum conductor is the ground and it runs from the ground buss bar in the house to the ground buss bar in the garage. If you feel uncomfortable making these connections, by all means, hire an electrician.

If you can dig the trench and run the conduit you will save big bucks. Electricians charge the same hourly rate for digging as they do for working with wire.

Making the connection at the house panel and bringing the cable to the exterior is going to be the hardest part of this job. If you have trouble figuring how to do it get back to us with some photos and drawings.

This advice is most likely to late for you but I recommend a "Combo" meter base for almost all new home construction or when the service is upgraded. A combo meter base has three sections, the meter base at the top, a circuit breaker type disconnect in the middle (sometimes called a fireman's switch), and, at the bottom, four to eight circuit breaker positions. With this base, adding future circuits for a new garage, swimming pool, or other purpose is much simplified. A combo base costs about $100-120. In some cases, swapping the old meter base for a combo is simpler and more cost effective than tunneling through wall to reach the existing service panel.

Thanks a lot for the response. The run is right at 100 feet. Both panels are in exterior walls. Do you have any suggestions on what type of panel to get for the garage?

 

[stroked89coupe]

So i should have a 90 amp beaker in the house panel and then another 90 amp main breaker for the secondary panel in the garage?

 

[brewchief]

So i should have a 90 amp beaker in the house panel and then another 90 amp main breaker for the secondary panel in the garage?

You can use a 90 amp breaker in the house panel and a panel with a 100 amp main breaker in the garage.

The more spaces in the garage panel the better.

Many folks here prefer to use the same brand and type of panel in the garage as the house but it's not necessary.

 

[stroked89coupe]

You can use a 90 amp breaker in the house panel and a panel with a 100 amp main breaker in the garage.

The more spaces in the garage panel the better.

Many folks here prefer to use the same brand and type of panel in the garage as the house but it's not necessary.

So the 100 amp main breaker in the garage is basically just serving as a disconnect while the 90 amp in the house is being matched to the conductor that is feeding the garage?

 

[Norcal]

2-2-2-4 would not be good for 100A on a sub panel. It is sufficient for supplying 100A service though, one of the interesting things about the NEC. So, you may need to install a 75A or 90A breaker (depending on cost/availability) if it is inspected.

If it is difficult to install a conduit, you could transition in a junction box to SER and run it in the house/shop if the installation permits. If it's a simple straight run, you can definitely go all the way in with MHF and conduit.

2 AWG AL is only suitable for 100 amperes if supplying the ENTIRE load of a dwelling and a dwelling only.

 

[Charles (in GA)]

So the 100 amp main breaker in the garage is basically just serving as a disconnect while the 90 amp in the house is being matched to the conductor that is feeding the garage?

That is correct.

 

[ishiboo]

2 AWG AL is only suitable for 100 amperes if supplying the ENTIRE load of a dwelling and a dwelling only.

I am aware the NEC calls out "entire dwelling", but not "a dwelling only". Am I wrong here? IE, my understanding is you can run #2 AL to the main panel protected at 100A, then you could run a 100A sub panel off that to an outbuilding with proper sizing (#1 AL). In addition, I believe calling out "entire dwelling" is because you might have a fused/breakered disconnect outside, which then feeds the main panel... so they are extending this exception.

My assumption is that this is allowed because a residential building's duty cycle and uses rarely causes the main service to be at 100% of capacity for any extended period of time.

If you had a 400A service in a commercial setting, and ran a 100A sub it could be for a 100A piece of equipment that runs all the time, so the undersized feeder is no longer appropriate.

Likewise, in a residential subpanel, I don't see an issue with installing a less expensive 100A breaker to feed a 2-2-2-4 sub panel safety wise, although it is in violation of code. Unless you plan on using that extra capacity over an extended period, of course... in which case you likely should install a 150A or 200A service.

 

[Charles (in GA)]

I am aware the NEC calls out "entire dwelling", but not "a dwelling only". Am I wrong here? IE, my understanding is you can run #2 AL to the main panel protected at 100A, then you could run a 100A sub panel off that to an outbuilding with proper sizing (#1 AL). In addition, I believe calling out "entire dwelling" is because you might have a fused/breakered disconnect outside, which then feeds the main panel... so they are extending this exception.

My assumption is that this is allowed because a residential building's duty cycle and uses rarely causes the main service to be at 100% of capacity for any extended period of time.......................................

(7) 120/240-Volt, 3-Wire, Single-Phase Dwelling Services
and Feeders. For individual dwelling units of one-family, two-family, and multi-family dwellings, conductors, as listed in Table 310.15(B)(7), shall be permitted as 120/240-volt, 3-wire, single-phase service-entrance conductors, service-lateral conductors, and feeder conductors that serve as the main power feeder to each dwelling unit and are installed in raceway or cable with or without an equipment grounding conductor. For application of this section, the main power feeder shall be the feeder between the main disconnect and the panelboard that supplies, either by branch circuits or by feeders, or both, all loads that are part or associated with the dwelling unit. The feeder conductors to a dwelling unit shall not be required to have an allowable ampacity rating greater than their service-entrance conductors. The grounded conductor shall be permitted to be smaller than the ungrounded conductors, provided the requirements of 215.2, 220.61, and 230.42 are met.

No, they mean the main service from the meter to the panelboard.

 

[ishiboo]

No, they mean the main service from the meter to the panelboard.

I'm confused here... I read what you cited and it seems to jive with what I said?

"For application of this section, the main power feeder shall be the feeder between the main disconnect and the panel board"

Not quite sure what this means though. Most houses do not have a main disconnect between the meter and the panel board.

 

[stroked89coupe]

If someone could help me out I have a few more questions.



I trenched 85 feet of 2-2-2-4 and finished up running my cat5 and RG6 today. I went to get a panel from Lowes and kind of got confused. I asked a guy what he recommends and he did not give me any good suggestions.

He mentioned square D breakers. It appears that Square D breakers are the same size as a regular breaker but can power two circuits. So the only real benefit to this that I can see is space savings or if you are running out of room in your panel these may get you out of a bind. Am I far off here?

Do square D's require a special panel? I want big panel so that I will have lots of available circuits later down the road. Size does not matter. If I had to put a number on it I would say that I probably want 5 to 8 slots left over. I will probably use 5 to 8 as well.


Can any one help me out with a panel selection? I know I want 100 amp service. And there is about 8 different 100 amp panels to choose from at lowes.

I just want to make sure I don't screw myself and get a panel that only accepts a certain kind of breaker (I don't even know if that's possible). From the looks of things it many looks like the only real difference is brand and the actual size of the panel.

 

[Aceman]

What kind of panel do you have in your home? I usually match it unless it's something with aluminum buss.

 

[stroked89coupe]

What kind of panel do you have in your home? I usually match it unless it's something with aluminum buss.

It's a 200 amp panel that was updraged fro 150 amp service about a year ago. It's a GE PowerMark Gold Panel.


What ever that means.

 

[msgross]

What kind of panel do you have in your home? I usually match it unless it's something with aluminum buss.

I agree, just get a 20 space breaker box from the store, they usually have combo packs that come with a few 20-30 amp breakers included.

I have the BR type breakers in my house so i'm getting this one. 2-2-2-4 MHF can direct bury but i'm doing conduit outside and an 8x8x4 junction box inside and splicing to 2-2-2-4 SER so I don't have to run conduit inside.

http://www.homedepot.com/p/Eaton-10...=REC-_-PIPHorizontal1_rr-_-NA-_-100168474-_-N

 

[Dagny]

Cutler hammer CH panels best square D QO next best. Don't really care for any of the others . However the others are cheap.

 

[toplessHO]

I agree, just get a 20 space breaker box from the store, they usually have combo packs that come with a few 20-30 amp breakers included.

I have the BR type breakers in my house so i'm getting this one. 2-2-2-4 MHF can direct bury but i'm doing conduit outside and an 8x8x4 junction box inside and splicing to 2-2-2-4 SER so I don't have to run conduit inside.

http://www.homedepot.com/p/Eaton-10...=REC-_-PIPHorizontal1_rr-_-NA-_-100168474-_-N

I would go with a 12x12x6 or 8 box.
and chosing a CH over a SqD QO panel is a first for me.
I would always go with the SqD

 

[stroked89coupe]

What is a QO brand?


Is GE/Seimens ect no good? Or is it just consumer grade junk?


I'm sure it's best to go with the same brand breakers as the panel?

 

[brewchief]

What is a QO brand?


Is GE/Seimens ect no good? Or is it just consumer grade junk?


I'm sure it's best to go with the same brand breakers as the panel?

QO is one of square Ds lines, Homeline is the other, QO is considered a better quality line.

Brand and type of breaker need to match the panel, in some cases other brands may fit but unless they are listed to be used with that panel they should not be used.

 

[stroked89coupe]

QO is one of square Ds lines, Homeline is the other, QO is considered a better quality line.

Brand and type of breaker need to match the panel, in some cases other brands may fit but unless they are listed to be used with that panel they should not be used.

Ok cool. Thanks a lot for the help. I did notice the homeline brand at Lowes.

 

[stroked89coupe]

Some random questions....


Does anyone know how many wires can be fastened in the middle of the 2x4 (Within 12'' of the box I think is code?) with one staple?


So in other words I'm assuming if I have three switch legs going to a three gang box, Does each of those switch legs have to have a separate staple?

 

[stroked89coupe]

Also,


If I have 6 outlets that I want to run in a series, or tie together, on the same breaker (Just as an example) that span across the entire wall, Is there a specification that states where to drill the hole at in the 2x4 that the wire passes through to get to the next outlet?


I know it has to be in the middle of the stud, but is there a height requirement or a certain distance from the top of the box ect?

 

[Charles (in GA)]

What is a QO brand?


Is GE/Seimens ect no good? Or is it just consumer grade junk?


I'm sure it's best to go with the same brand breakers as the panel?

Siemens is an excellent panel, just be sure and get one with a copper bus. They make both aluminum and copper. The AL will eventually corrode at the point where the breakers fit the stabs.

While some disparage GE panels, I have never had a minutes trouble with the ones I have used and they use tin plated bus, some Aluminum, some Copper, make sure you know what you are getting. The Power Mark Gold is the better GE line and I think it has Copper bus's in it, but check to make sure.

 

[stroked89coupe]

I have an aluminum bus in my main panel. Or what apears to be aluminum.


So an upgraded copper bus for the main panel would not be a bad idea huh?

 

[stroked89coupe]

Some random questions....


Does anyone know how many wires can be fastened in the middle of the 2x4 (Within 12'' of the box I think is code?) with one staple?


So in other words I'm assuming if I have three switch legs going to a three gang box, Does each of those switch legs have to have a separate staple?

Also,


If I have 6 outlets that I want to run in a series, or tie together, on the same breaker (Just as an example) that span across the entire wall, Is there a specification that states where to drill the hole at in the 2x4 that the wire passes through to get to the next outlet?


I know it has to be in the middle of the stud, but is there a height requirement or a certain distance from the top of the box ect?

Anyone?

 

[unsinkable]

Stroked,
art.300.4 (A) (1) - Cable (hole) must no closer than 1 1/4 in. from the edge of the framing member. Or else use a nail plate on edge of stud, to keep nails or sheetrock screws from reaching wire.

I usually will put two stacked 14 ga nm (romex), or a 14 and a 12 stacked using standard length staples, longer staples if two 12's, DO NOT beat the bag out of the staples, it will crush the conductors, tight is tight. If short on space, stagger the staples so you can lay cables flat and along side each other.
Yes,must be secured at least every 4 1/2 ft, and within 12" of a box.
No height requirement for hole, just make wire can be molded down (or up) to box with NO HARD angles...all cables should be somewhat relaxed at 90's.

NEC can be viewed online for free, article 300 will give you more info.

Good luck !