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Help w/ Portable Sub-Panel Install


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Hey guys-

Been reading a ton, asked a lot of questions to my local Home Depot electrician- but want to run this by you guys before I proceed.

I've installed a lot of breakers & additional outdoor receptacle/outlets in the past, and I have a good general idea- but need specifics.

I need more power. It must be portable as I will be moving in a year or two and don't want to uninstall a ton of receptacles, etc. I want to be able to wheel the 'Wall of Power' out when I need it, plug it in, then wheel it back into the garage when I'm done.

I currently have a 200a servicing running into my house. I'm thinking I would install/build a 100a sub-panel w/ a dryer cord receptacle to connect the two when needed.

So, I'll install a 50a single pole breaker into the existing Main. I'll run 6/4 from that into a single weatherproof box w/ dryer receptacle. That will stay connected until I move. Good so far?

That will connect with a 6/4 cord where I will have installed the male dryer plug on one end, and hard wire the other end into the 100a panel. Inside that panel I'll have 5, 20a circuit breakers. THOSE are then connected using 12/2 wire from the breakers to the receptacles. Correct?

And yes, I've got it pre-configured to stay at 80% MAX on any/all outlets/sources, etc. I'll shut off the main completely when I'm even THINKING about touching anything in or around there, etc etc.

QUESTIONS-

1) I want to minimize that amount of actual plugins as possible. I just need one plugin for every 20a source. So, for example- is it possible to have a single receptacle (2 plugins total) that runs 20a at each plugin (so 40a for the BOTH of them combined)? Or, do I have to run 20a total across the entire receptacle (both plugins)?

2) Depending on answer to #1 above- is it possible to not use receptacles AT ALL, and just use dongles (like the kind you see hardwired into the LOR boxes)? I know it's the acceptable method to use receptacles/outlets- however- if the breaker is to trip at 20a, what's the point of receptacle boxes if I only need a single plug? Just more expense and time to hook up. It'd be sweet if I could just hookup the female end dongles right to the subpanel/breakers and then out of the box itself. Each dongle would then carry a max of 20a per cord. If this is possible, where' the best place to buy these dongles?

3) Can I add MORE than 5, 20a breakers/receptacles? Someone told me I could go up to 6 total- but I didn't understand how.

See anything I'm missing, or important things to note before I begin this journey here?

Thanks for the help!

Edited by azspecter
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Well for starters if you're planning on pulling the potential for 80A (80% of 100A) then your 30 Amp dryer recptacle will melt down, that device is rated for 30 Amp period nothing more regardless of temporary useage. Secondly each receptacle needs to be a dedicated circuit, you can't have more than one power source per receptacle. All of the receptacles need to be GFCI receptacles or use GFCI breakers. The receptacles need to be weater resistant and tamper resistant as well as installed with a weatherproof in use cover. Don't know what 100A sub panel you're planning on using but it needs to be rated for outdoor useage ie: NEMA 3R.

Tony

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Thank you for the reply. Yes, I'm planning on using the 50a/240v plug/cord etc. It may not be a Dryer plug- but it's the one with 4 pins/wires... DEFINITELY 50amp tho...

I'm also going to be using outdoor rating on everything, and then build a contained box to mount it in. I may even go as far as bungee cording a tarp over the entire thing once it's all up and running- just to play it safer.

ok- so for each receptacle (2 plugins) I can only have 20amp going to it. Got it. I looked at what I used to have, that's what it was. I'll just have a 'dead' plug on each one, maybe I'll rig up an indicator light to show when it's hot or something on that outlet.

I guess the only way I can squeeze MORE receptacles in is if I drop my amps down to 15 each instead of 20, right? Then I could utilize a 6th outlet box. I'll have to take a look at my LOR controllers and see if I ordered the upgraded 40a ones, or have the regular 30amp ones. That might change things for me.

Question- if I drop it down to 15a per circuit and breaker- could I use dongles instead of receptacles/outlets? I was thinking of something like this-

http://store.lightorama.com/rewigr18.html. I could wire these cords DIRECTLY to the breaker, and avoid the entire electrical box/receptacle all together, correct??? Seems silly, expensive, and time consuming to have boxes when you don't need to. Am I missing something?

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If you're going to use a 50A range receptacle that may be problematic as I don't think you will find one that is outdoor rated and if you're going to go that route why not do a 50A douple pole breaker which will give you 50A at 240V or 100A at 120V.

I would recommend you look for a pin and sleeve receptacle and cord end, as they are weatherproof and designed for repeated connect/disconnect cyles, your standard range receptacle is really designed for plug it in and forget it type useage.

You'll still need either GFCI breakers or receptacles, you can use the dongles but that will force you into the GFCI breakers which are approximately $30.00 each.

Tony

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I also use a 50 amp Range cord, it plugs into a RV outlet box I bought at Lowes for $25 it is rated for external use. It look just like this one but it was the 50amp model. The cord then feed a sub panel that was mounted in a box that was built for exterior with 10 dedicated GFI circuits mount with it.

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Yeah, talked to another guy at Home Depot- he helped me a ton. I'll be using an outdoor rated 4 pin receptacle- don't think it's a range one, but it's one made for that type of usage. Any idea on the best place for a pin and sleeve receptacle/plug? Does Home Depot/Lowes have those rated at 50a? I'll also use a Double Pole 50amp breaker. He didn't know if that converted to 100a @120v or not, but you guys confirm that it does.

Dang- great point on the GFCI breakers. I had NO IDEA they were that expensive. That really defeats the purpose. For that much in price difference, I'd rather spend a little more time/effort wiring up outlets instead.

Question: These boxes all say 6 spaces, 12 circuits. I assume that I can ONLY get 12 circuits if I use the double/streamline type breakers, correct? If that's the case, and I'm running a 50a dual pole breaker on the main- how many amps can each receptacle handle if I'm running 12 circuits instead of only 6?

Question: How do you guys wire up your receptacles/outlets themselves? If, for example, you have 15a running to a receptacle- there's (2) actual plugins per receptacle. Does EACH plugin get 15a, or is the 15a split between the two plugins- effectively giving you 7.5a per plugin?

Question: The Home Depot guy told me that if I'm running 50a- I need to use 8 guage wire from the 50a breaker to the 4-pin receptacle, and then 8 guage from the receptacle to the subpanel. He also told me that if I'm running 15a, I use 14guage, and 12guage for 20a. Is this correct?

Question: Box Construction- I assume most of you use 2x4's and plywood. I saw one guy use an exterior rated metal cabinet to house all this- those things are expensive. Do you guys build it all self-contained with a front door that closes and a gap at the bottom for all your cords to run out of? Do you build a removable back panel so that you can access all the wiring without tearing the entire thing apart? Very curious as to the best/easiest way to build this thing.

Thank you for all the help!!!

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Yeah, talked to another guy at Home Depot- he helped me a ton. I'll be using an outdoor rated 4 pin receptacle- don't think it's a range one, but it's one made for that type of usage. Any idea on the best place for a pin and sleeve receptacle/plug? Does Home Depot/Lowes have those rated at 50a? I'll also use a Double Pole 50amp breaker. He didn't know if that converted to 100a @120v or not, but you guys confirm that it does.

Dang- great point on the GFCI breakers. I had NO IDEA they were that expensive. That really defeats the purpose. For that much in price difference, I'd rather spend a little more time/effort wiring up outlets instead.

Question: These boxes all say 6 spaces, 12 circuits. I assume that I can ONLY get 12 circuits if I use the double/streamline type breakers, correct? If that's the case, and I'm running a 50a dual pole breaker on the main- how many amps can each receptacle handle if I'm running 12 circuits instead of only 6? - well if you just do the simple math a 50amp 220v sub panel is like 100amp 110v if you only use 110v breakers, 100amp/12 = 8.33 amps per circuit. I would get a copy of the power spreadsheet from this website it will allow you to better balance your loads. You will end up with a couple that may be at 10amps and some at will will be less.

Question: How do you guys wire up your receptacles/outlets themselves? If, for example, you have 15a running to a receptacle- there's (2) actual plugins per receptacle. Does EACH plugin get 15a, or is the 15a split between the two plugins- effectively giving you 7.5a per plugin? It is a total of 15amps for the outlet, but you can balance it to 7.5 per side if that helps you.

Question: The Home Depot guy told me that if I'm running 50a- I need to use 8 guage wire from the 50a breaker to the 4-pin receptacle, and then 8 guage from the receptacle to the subpanel. He also told me that if I'm running 15a, I use 14guage, and 12guage for 20a. Is this correct? - I would only use 6 gauge for 50 amps,

Question: Box Construction- I assume most of you use 2x4's and plywood. I saw one guy use an exterior rated metal cabinet to house all this- those things are expensive. Do you guys build it all self-contained with a front door that closes and a gap at the bottom for all your cords to run out of? Do you build a removable back panel so that you can access all the wiring without tearing the entire thing apart? Very curious as to the best/easiest way to build this thing. I used 1x6's and MDO plywood, the whole front is a door that swigs up to open.

Thank you for all the help!!!

See everything in the red

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Awesome. Do you have a thread or pics of your subpanel that I can see? Thanks for all the help!

Sorry I'm coming to this thread so late... Last year I did what you're looking to do and created a detailed post here. I wasn't the first, you might want to try searching for some of the others. Here is mine:

http://forums.planetchristmas.com/showthread.php/37800-New-200A-rated-weatherproof-porta-power-unit?highlight=panel

Couple of things because you brought up the issue of cost....

1. Those outdoor-rated RV enclosures are only $24 at Home Depot / Lowes. They are weatherproof and they are 50A-rated. http://www.homedepot.com/h_d1/N-5yc1vZ1xg3/R-100565603/h_d2/ProductDisplay?langId=-1&storeId=10051&catalogId=10053

2. My 125A outdoor-rated subpanel that I have hte RV outlet connected to was only $30-ish off the internet. Buy.com has it for $44 shipped, I'm sure you can find it cheaper http://www.buy.com/prod/eaton-electical-cutler-hamm-br612l125rp-125a-lug-load-center/q/sellerid/29137557/loc/66357/204608886.html

You can do this on the cheap without resorting to the use of MDF/plywood/two-bye material... Build it to last the first time so you don't have to redo it later.

Lastly, I was going for something heavier duty that you, which is why I went the route of the dual sub-panels feeding the large Hoffman enclosure... If I were you, I would buy the RV outdoor enclosure, a range plug that is 50A-rated, an outdoor 125A load center that has 8 slots capable of holding 16 circuits (way more than you will run off 100A) and you will be set.

PM me with more questions, I might not make it back to this thread, but I'm willing to help.

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http://cgi.ebay.com/Hoffman-A363608LP-Wall-Mount-Type-12-13-Enclosure-New-/200546663098?pt=BI_Electrical_Equipment_Tools&hash=item2eb1833aba

eBay is where I got mine. I think I paid $80-100 for it and another $40 to ship. It took a while to find a good deal and mine is used... but it looked new to me and works just as well. I added weatherstripping to mine to make it tighter. I think I have a bunch of pictures of it in the link I sent earlier, let me know if there aren't any there and I can send you more detailed pics.

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sounds a little like what i did. I got a 100 amp surface mount panel from www.jamestownadvanced.com $120 then i got 2 spider boxs off ebay $250 and 150 foot of 6/4 soow from a auction

for $50. I had room in my panel to install a 100 breaker. mounted the panel on the side of the house, run one spider box to one side of the yard and the other to the other side. Sure beats having exrtenstion cords running to every outlet i got. The wife said i was crazy untill she didnt see any cords running every where. When i move in a few years i take the panel off the house replace 2 pieces of sideing patch the hole.

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sounds a little like what i did. I got a 100 amp surface mount panel from www.jamestownadvanced.com $120 then i got 2 spider boxs off ebay $250 and 150 foot of 6/4 soow from a auction

for $50. I had room in my panel to install a 100 breaker. mounted the panel on the side of the house, run one spider box to one side of the yard and the other to the other side. Sure beats having exrtenstion cords running to every outlet i got. The wife said i was crazy untill she didnt see any cords running every where. When i move in a few years i take the panel off the house replace 2 pieces of sideing patch the hole.

Bingo. It got to the point where, when I jumped to 11 controllers from 7, each requiring two cords, that I no longer had "just" 14 cords running out of the garage, but 22 cords (and they are the 12 gauge cords to carry 15-ish Amps). It was a nightmare running those cords out of the garage... shoot, I didn't even like running 14 cords out of the garage, but I did... It is so much nicer now. I have the CAT5 still running out under the garage door and a couple of non-GFI circuit cords running out just in case there is a night where I NEED something to go on, but the GFI is tripped... that is much better than it was.

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ok- so for each receptacle (2 plugins) I can only have 20amp going to it. Got it. I looked at what I used to have, that's what it was. I'll just have a 'dead' plug on each one, maybe I'll rig up an indicator light to show when it's hot or something on that outlet.

Do it the easy way. Just plug a nightlight into the second (unused) spot. There's no need to build a special indicator light. :D

I guess the only way I can squeeze MORE receptacles in is if I drop my amps down to 15 each instead of 20, right? Then I could utilize a 6th outlet box. I'll have to take a look at my LOR controllers and see if I ordered the upgraded 40a ones, or have the regular 30amp ones. That might change things for me.

Well, yes and no. For the most part I think you are thinking about it correctly. However, if you look in the average breaker box and add up the amp rating of all the breakers, you will frequently find that the total number of amps is more than the amp rating of the main breaker switch. Since the circuits are not ever (we hope) used all at the same time at maximum load it doesn't cause a problem. You could wire up all six circuits in your box as 20 amp circuits but if you go over 100 amps total on the box you'll trip the breaker it's connected to. I like the idea of it being a little heavier duty than necessary but there may be some issues that I'm not thinking of at the moment. Maybe Tony can comment on whether this would present any problems in terms of either code or safety issues.

I'll also use a Double Pole 50amp breaker. He didn't know if that converted to 100a @120v or not, but you guys confirm that it does.

Just to clarify, it doesn't "convert" to 100 amps. A double pole breaker is essentially 2 breakers in one that are switched simultaneously by a single switch. Each pole of a double pole breaker connects to one of the hot "legs" in the breaker box. Each leg is 120 volts. A 50 amp double pole breaker therefore switches 2 separate loads of 50 amps @ 120 volts. The 2 poles can either be used together to provide 50 amps @ 240 volts or separately to provide 50 amps each @ 120 volts (for a total of 100 amps @120 volts).

TED

Edited by TED
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