New garage needs power

[averagehack]

I am doing a very similar instalation and have one question. (OK...probably more than one eventually)

From my main panel at the house I will have a 90 amp breaker feeding the MHF 2-2-2-4. does the MHF wire need to go dirrectly to a conduit to run through the house walls? I know it does if exposed like outside our in the shop but...?

Thanks

 

[pattenp]

MHF needs to be in conduit when inside the structure. No exceptions.

If more questions, you should start your own thread.

I am doing a very similar instalation and have one question. (OK...probably more than one eventually)

From my main panel at the house I will have a 90 amp breaker feeding the MHF 2-2-2-4. does the MHF wire need to go dirrectly to a conduit to run through the house walls? I know it does if exposed like outside our in the shop but...?

Thanks

 

[Maxtork]

Actually Averagehack brings up a good question. Since I will be using the 2224 MHF wire will it have to be in conduit where it runs through the attic of the house from the main panel? I was going to leave it exposed in the attic like the rest of the romex up there and start the conduit once it drops down through the soffit at the corner of the house where it will run along the outside of the wall into the trench. I would really like to not have a big run of conduit running down the outside corner of the house either but I didn't figure I could get away with that as it is totally exposed. Up in the attic though I thought I could get by with that one.

Whaddoyathink?

Max

 

[pattenp]

MHF is individual conductors not wrapped in an overall sheathing such as NM-b or SER so it needs to be in conduit where installed inside the structure. It's the same as running individual THHN conductors, needs to be in conduit. You can use SER from the panel through the attic and transition to MHF by using a large PVC junction box. Otherwise you need to run conduit in the attic.

 

[Maxtork]

Well ****....guess I better adjust plan accordingly. I really don't want to run a bunch of extra conduit. Is SER comparable in price to MHF? I was already considering adding a few feet to the underground run and installing the panel on the other side of the door to avoid moving studs around. Now if I have to make 30 ft of that run in some high dollar cable I'm gonna be bummed.

Thanks for all the help
Max

 

[pattenp]

Aluminum 2-2-2-4 SER is about the same price, maybe a few cents per foot more. The large PVC jbox and fittings and splice connectors aren't cheap. You'll need at least a 8x8x4 jbox for making up the splices.

 

[Maxtork]

Well I guess its off to the electrical supply store I go. Thanks for the help.

 

[Maxtork]

Well I'm almost ready to dig my trench and make my main run from the house to the garage. I ran across this wire online and was wondering if this would work.

http://www.wireandcabletogo.com/2-3-4-ground-SER-Aluminum-Building-Wire.html

I will run sch 80 conduit from the garage down through the trench and up the side of the house. If I use the wire linked above could I run it through the attic without conduit since it is SER and has an outer covering? As I understand it this is what is missing from the MHF that prevents it from being run through the attic unless it is in conduit.

The price for the SER is about what I was expecting for the MHF. Since I'm going to run conduit underground I don't really need the direct bury rating of the MHF although if the SER is good for direct bury I could eliminate the conduit through the trench and just use the sweeps and vertical sections at either end. Either way if I have this sorted out right I would avoid a splice at the attic and or conduit through the attic.

What do you think?

Max

 

[Maxtork]

Actually this is a link to what I think is the same wire at my local electrical supplier.

http://www.mayerelectric.com/itemDetailFilterPH.action?codeId=1064098

So this is what I would be using. I was there today and asked about what they recommended and as soon as I told them I would be inspected by the county he clammed up and told me to call them and ask. I really want to do this "right" and not just "right enough". Knowing my luck it will come back to bite me if I cut a corner.

Thanks
Max

 

[Charles (in GA)]

You CANNOT put SER in the ground, period, not exposed, or in conduit. NEC 338.12(A).

I just looked this up this evening, because the electrician who wired the panel in our community well house used USE-2 that is not rated any other way. Its less than a 2 ft run and I'm going to replace it with #2 or #3 copper THHN, as I clean up the mess left by the electrician and a neighbor who did a non-code generator connection.
Charles

 

[Maxtork]

You CANNOT put SER in the ground, period, not exposed, or in conduit. NEC 338.12(A).

I just looked this up this evening, because the electrician who wired the panel in our community well house used USE-2 that is not rated any other way. Its less than a 2 ft run and I'm going to replace it with #2 or #3 copper THHN, as I clean up the mess left by the electrician and a neighbor who did a non-code generator connection.
Charles

Well ****...back to plan B again. You would figure that someone would sell a cable that can run underground and through an attic. Oh well I guess I will have to put a junction box in the attic and switch from MHF to SER there.

Ya'll know I would pay quite a bit of beer for one of you smart guys to come down here and do this for me. The wife would shoot me for paying someone in dollars but beer I can get away with lol.

Max

 

[Mustang51js]

You also don't need schedule 80 unless there's more than two feet of concrete in front of it and even if there was you only need it down and on the sweep into the ground,everything underground can be schedule 40. Saves some money there.

 

[2ManyProjects]

Well I'm almost ready to dig my trench and make my main run from the house to the garage. I ran across this wire online and was wondering if this would work.

http://www.wireandcabletogo.com/2-3-4-ground-SER-Aluminum-Building-Wire.html

That would be fine for the portion of the run from the panel up through the attic and to the junction box suggested by "pattenp". No conduit necessary until you transition to the 2-2-2-4 MHF in that junction box.

I will run sch 80 conduit from the garage down through the trench and up the side of the house.

Assuming you're still planning to use MHF for that underground run out to the shop/garage, there's really no need for putting it in conduit the whole way. You WILL need conduit for any "exposed" portions of that run; which effectively means from that attic-mounted junction box down the outside of the house and into the ground where you use a large-radius "sweep" elbow to get to the final trench depth. From there on out to the shop (where you'll use another sweep elbow and more PVC to get to the sub-panel), no conduit is required. That said, some folks do like to use conduit the whole way, "just because"; but this would be a PITA to pull through.

If I use the wire linked above could I run it through the attic without conduit since it is SER and has an outer covering? As I understand it this is what is missing from the MHF that prevents it from being run through the attic unless it is in conduit.

Correct.

The price for the SER is about what I was expecting for the MHF. Since I'm going to run conduit underground I don't really need the direct bury rating of the MHF although if the SER is good for direct bury I could eliminate the conduit through the trench and just use the sweeps and vertical sections at either end. Either way if I have this sorted out right I would avoid a splice at the attic and or conduit through the attic.

Nope. As Charles mentioned, SER cannot be used underground, period. Now, IF you happen to find some multi-rated SER/USE-2 cable at a reasonable price, that could potentially be used for the whole thing. But IMCO, it's just not worth the hassle (and likely expense). It's easy enough to make that one transition from SER to MHF where the cable leaves the attic, as discussed earlier.

Actually this is a link to what I think is the same wire at my local electrical supplier.

http://www.mayerelectric.com/itemDetailFilterPH.action?codeId=1064098

So this is what I would be using.

Yes, that appears to be the same stuff.

I was there today and asked about what they recommended and as soon as I told them I would be inspected by the county he clammed up and told me to call them and ask.

No surprise. They don't want you coming back and bitching at them if/when the inspector fails you for whatever reason (related to their advice or not).

 

[Maxtork]

Thanks 2many. I think I will go with the mhf and ser combo as this will be easiest. Question though...if I dont run conduit the whole way underground do you have to seal the open ends of the sweeps y o the cable? If so how is this done?

Also do you guys just use the split bolts and tons of tape for the ser to mhf junction? Or do you use the fancy mechanical connectors?

Thanks
Max

 

[Mustang51js]

Ou have to run it the whole way underground,the part he was talking about not running pipe is after you enter the structure

 

[pattenp]

If the conduit is just being run for the outside exposed part to below ground with sweeps ending in the bottom of the trench, the open end does not need to be sealed, just leave it open. This is provided you are using MHF for the run underground. MHF is direct bury cable.

 

[HotwheelsYJ]

I know most of your questions this far have been getting power to your building. For that I have no advice since my meter is mounted on the back of my 200 amp breaker box. But to save some time & worry, ask your inspector what the minimum work required is to have inspection.

For Bradley county in TN, all he needed was 1 GFI outlet & 1 switched light to sign off on the inspection. I useda 8' sectipn of conduit to cover everything. GFI outlet is straight out the bottom of the box. Light switch is mounted to the side of the box and the rest of the conduit round straight out the top with a flood lamp mounted on the end. All other wiring will be done at my leisure post-inspection

 

[Maxtork]

Thanks Guys,

I thought about doing what hotwheels suggested and just doing the bare minimums but I the inside stuff isn't to hard so I went forward with most everything I would want. I only have a few hours of running wire before I'm done anyway.

PattenP...I will be using MHF for the underground portion so I will probably just use conduits at either end as you suggested.

Has anyone used this type of connector for MHF to SER?http://www.grainger.com/product/POLARIS-Insulated-Connector-14V980?s_pp=false


I'm not sure if each section is a splice by itself or if this would tie all the wires together (obviously a no-go). This would be great if I could use something like this to connect each leg of the MHF to each leg of the SER. I know they make smaller versions but they are pricey so buying one big one would be cheaper than 4 smaller ones.

Thanks
Max

 

[theoldwizard1]

Also do you guys just use the split bolts and tons of tape for the ser to mhf junction? Or do you use the fancy mechanical connectors?

Has anyone used this type of connector for MHF to SER? http://www.grainger.com/product/POLARIS-Insulated-Connector-14V980?s_pp=false

I would use split bolts although I don't know it they are acceptable for aluminum wire. Much cheaper. Use old fashioned friction tape.

 

[kenfath]

The suggestion of placing receptacles 48/52-inches above the floor seems to be common advice from GJ.com members. This is a good height for workbenches, tools like the pedestal grinder or drill press where you want to keep the cord off the floor, and yes the 4-foot panels that may be placed against the walls. However there are locations where receptacles at other heights can be advantageous. 18 or 20 inches above the floor is a better height if the cord will be on the floor; ex. an extention cord. 60-72" would be suitable for the big screen TV or the decorative neon auto maker sign.

Make sure to include receptacles in the ceiling for the garage door opener, cord reel, etc.
Also, make sure to have an outside receptacle by the garage door. A friend put one on the backside of the garage and it proved to be very useful. Easy to do when the walls are opening and you are stringing wires.

 

[2ManyProjects]

The suggestion of placing receptacles 48/52-inches above the floor seems to be common advice from GJ.com members. This is a good height for workbenches, tools like the pedestal grinder or drill press where you want to keep the cord off the floor, and yes the 4-foot panels that may be placed against the walls. However there are locations where receptacles at other heights can be advantageous. 18 or 20 inches above the floor is a better height if the cord will be on the floor; ex. an extention cord. 60-72" would be suitable for the big screen TV or the decorative neon auto maker sign.

I'll concede the latter case, but only for those isolated locations where you already know you're going to be mounting such a device up high; so it's not an "on general principles" sort of thing. In the former case, I'd still go for keeping the bottom of the boxes above 48 inches (say 50 inches, just to be on the safe side). The extra two or three feet of "extension cord" which could effectively be required in some cases is trivial; and you still need to be able to get to the outlet after all manner of **** has somehow managed to "accumulate" in the garage, in order to plug that cord in.

Make sure to include receptacles in the ceiling for the garage door opener, cord reel, etc.

Cord reel, maybe. But NOT the GDOs, for at least two reasons:

First, if this is a new build (or a sufficiently extensive remodel) and you have your choice of GDOs, then a side-mount opener such as the LiftMaster 8500 will make for a MUCH neater, cleaner installation, without a belt/chain track cluttering up the center of the ceiling:

http://www.liftmaster.com/lmcv2/productdetail/19724/liftmaster-products/

Hence, no "middle of the ceiling" outlet is needed, either.

Second, and regardless of the type of GDO chosen, it really ought to be hard-wired, as opposed to using a plug & receptacle. Current NEC requires that ALL outlets in a garage be GFCI-protected; and GFCIs and motors can be a problematic combination. Since the GDO isn't going anywhere anyway, there's no real "up side" to being able to unplug it. If for whatever reason you want to completely remove power from it, just throw the breaker (or perhaps put in a switch if you anticpate doing that a lot).

Also, make sure to have an outside receptacle by the garage door. A friend put one on the backside of the garage and it proved to be very useful. Easy to do when the walls are opening and you are stringing wires.

For that matter, properly protected receptacles on at least each exterior wall is also a good idea, so as to have a convenient place to plug in such things as electric lawn/garden tools and such.

 

[Maxtork]

Thanks for all the info guys. I got the trench dug this past weekend.



I think I have almost everything I need to get it all hooked up....except time!

I do have one more quick question though. For the funny screws that hold the panel covers on...do you guys have a special tool for those or just a big flat tip screwdriver? Those things are mega tight and I don't want to strip them out.

Thanks
Max

 

[pattenp]

A #2 square tip driver should fit. Other than that... a big flat blade screw driver.

 

[Maxtork]

Thanks again pattenp. I got the square tip and it worked perfect. I was amazed that it worked. I was really cranking on it with the flat tip and figured for sure it would strip out the tiny square drive but it worked great.

Max

 

[bobbyu]

Maxtork,
what did you use to connect the Ser wire to the MHF? I'm planning a 3rd garage and was going to use MHF all the way till I read in your thread how it had to be in conduit inside the house. I might have to just go out of my main box on the basebent wall underground to my sub panel.
Thanks
Bob

 

[Maxtork]

Hey Bob,

I used split bolts and a bunch of tape to insulate each conductor. I put the splice area inside a lb style conduit body just inside the eaves. the split bolts were only a few bucks each and the SER wire was actually cheaper than the mhf!

Hope this helps

Max

 

[Charles (in GA)]

Hey Bob,

I used split bolts and a bunch of tape to insulate each conductor. I put the splice area inside a lb style conduit body just inside the eaves. the split bolts were only a few bucks each and the SER wire was actually cheaper than the mhf!

Hope this helps

Max

Be careful doing this, as most LB conduit bodies are not rated for splices in them. Do this only if they are specifically rated for splices in them. Otherwise, there are a number of good junction boxes you can install on the outside foundation wall that can be used.

Charles

 

[Charles (in GA)]

I know most of your questions this far have been getting power to your building. For that I have no advice since my meter is mounted on the back of my 200 amp breaker box. But to save some time & worry, ask your inspector what the minimum work required is to have inspection.

For Bradley county in TN, all he needed was 1 GFI outlet & 1 switched light to sign off on the inspection. I useda 8' sectipn of conduit to cover everything. GFI outlet is straight out the bottom of the box. Light switch is mounted to the side of the box and the rest of the conduit round straight out the top with a flood lamp mounted on the end. All other wiring will be done at my leisure post-inspection

I did the same thing. One GFCI receptacle next to the box with a switch and two 500w quartz flood lights mounted on a 12 ft high wall girt and spaced 30ft apart on a 60 ft wall, that got me past the inspection and sign off so the POCO could be authorized to connect power. That lighting worked for years, and I still use it unless I need lots of light. Everything else was added later.

Charles

 

[Maxtork]

Hey Guys,

I'm a bit behind as I screwed up my back last weekend but I am going to try to finish the rough in wiring so I can get the garage inspected. I still need one more box that I can use to make the splice. I was going to use an LB but after reading Charles post that might not be totally legal. I'm not overly concerned as the inspectors around here seem pretty loose but if I have to buy one anyway I might as well make it legal. I saw some big PVC junction boxes at home depot but they dont have any holes in them. Are you supposed to just drill them out for the conduit to enter ? Something like this:

http://www.homedepot.com/p/Carlon-6-in-x-4-in-Junction-Box-E987RR/100404096

Any ideas?

Max

 

[Charles (in GA)]

I went and looked at the NEC and realize I did not correctly state the code requirements for splices in conduit bodies such as an LB. Here is what it has to say...........

314.16
(C) Conduit Bodies.

(1) General. Conduit bodies enclosing 6 AWG conductors
or smaller, other than short-radius conduit bodies as described
in 314.16(C)(3), shall have a cross-sectional area
not less than twice the cross-sectional area of the largest
conduit or tubing to which they can be attached. The maximum
number of conductors permitted shall be the maximum
number permitted by Table 1 of Chapter 9 for the
conduit or tubing to which it is attached.

(2) With Splices, Taps, or Devices. Only those conduit
bodies that are durably and legibly marked by the manufacturer
with their volume shall be permitted to contain
splices, taps, or devices. The maximum number of conductors
shall be calculated in accordance with 314.16(B). Conduit
bodies shall be supported in a rigid and secure manner.

(3) Short Radius Conduit Bodies. Conduit bodies such as
capped elbows and service-entrance elbows that enclose
conductors 6 AWG or smaller, and are only intended to
enable the installation of the raceway and the contained
conductors, shall not contain splices, taps, or devices and
shall be of sufficient size to provide free space for all conductors
enclosed in the conduit body.

In addition, the above paragraph references another paragraph in the same section, this paragraph is rather general covering the fill for outlet, device and junction box fill in addition to conduit body fill. The only part of the rather lengthy section that appears to be relevant to splices in a conduit body is the following.............

314.16
(B) Box Fill Calculations. The volumes in paragraphs
314.16(B)(1) through (B)(5), as applicable, shall be added
together. No allowance shall be required for small fittings
such as locknuts and bushings.
(1) Conductor Fill. Each conductor that originates outside
the box and terminates or is spliced within the box shall be
counted once, and each conductor that passes through the
box without splice or termination shall be counted once.
Each loop or coil of unbroken conductor not less than twice
the minimum length required for free conductors in 300.14
shall be counted twice. The conductor fill shall be calculated
using Table 314.16(B). A conductor, no part of which
leaves the box, shall not be counted.

Oddly, Table 314.1(B) only goes up to AWG 6 conductor sizes, so it is not relevant here.

So ,in the end, make sure the conduit body has a volume stamped or marked on it, and splice away!

Charles

 

[Maxtork]

Cool thanks Charles. I will be heading in to town tomorrow to pick one up. I just home depot or lowes has them with the volume stamped on it.

Max

 

[pattenp]

If you are thinking of splicing 2-2-2-4 in a 2" LB body I do not believe it has the required volume for the splice. With splices you need to have enough wire where it will extend at least 6" out of the box opening. I really don't think you'll be able to fold up the wire to get it back into the LB conduit body.

Edit: The box you linked in post #69 is the proper style box to use for splices. You drill the openings with a hole saw.

 

[Maxtork]

If you are thinking of splicing 2-2-2-4 in a 2" LB body I do not believe it has the required volume for the splice. With splices you need to have enough wire where it will extend at least 6" out of the box opening. I really don't think you'll be able to fold up the wire to get it back into the LB conduit body.

Not sure I understand. Are you saying there must be 6 inches of wire on either side of the splice still inside the box? That would ea a 12" box which seem huge. I know I can make the splices on all four wires and get them inside but if it doesn't have enough volume to be legal then what would?

Like I said in the previous post I have seen some bigger boxes but how do you get the conduit tied in to it?

Max

 

[Maxtork]

Ok sorry I didn't see your edited post before I replied. I can get one of those and drill the holes out.

Thanks
Max

 

[pattenp]

The ends of the wires are to have enough length that they will stick out past the face of the box at least 6". This is to prevent the wire from being cut too short so if a future repair is needed you are not left with wire ends too short to make up the splice. Having to leave that much length requires having a box large enough to be able to fold the wire into.

There are glue in fittings for connecting the conduit to the holes you drill in the box.

 

[Maxtork]

Ok I get it. Makes sense I guess. I will pick up one of the bigger boxes tomorrow. That should make it easier to fit it all in anyway.

Thanks
Max

 

[pattenp]

This is a box adapter....

http://www.cesco.com/b2c/product/334548

 

[Maxtork]

This is a box adapter....

http://www.cesco.com/b2c/product/334548

Does the flange go on the inside or the outside of the box?

 

[pattenp]

The box adapter installs from the inside. Then you slip on a coupling on the outside for the conduit connection.

 

[Maxtork]

Ok got it