|
| Author |
Message |
saskboy
Member
|
# Posted: 22 Feb 2014 09:13am
Reply
I wanna sort things out before we wire our little hunting shack, my problem is that I have a generator that only puts out 120v. Now there is the possibility of hooking up 240v years down the road, so I want to put in a small breaker box. To get the whole panel lit up I would need 240v with the two hot legs energizing both sides of the panel. Now is it possible to just jump the one hot leg from my 120v source to the other hot leg so my whole box is powered. Keep in mind this is not going to be hooked up to any 240v utility line while this is in use, but would like to have the option one day. Has anyone done this? I know this is against code but I dont care, no insurance, private land, nobody will care.
|
|
sparky1
Member
|
# Posted: 22 Feb 2014 09:22am
Reply
if you just have 120 V just use one side. one leg of the panel.
Every other connection should be hot.
so not to be a hazard later. when 240 is run into this panel.
you could mark the panel ( 120 volts only)
I did this when I started with 12 volts off a battery for lights. I marked the panel 12 volts DC only.
|
|
bldginsp
Member
|
# Posted: 22 Feb 2014 09:57am
Reply
I don't see how jumping the two hot legs would create any hazard so long as you have only one hot lead coming in. It just gives you that many more breakers to use. Surprised your generator has no 240, most do. Make sure your grounds are bonded to the neutrals either in the generator (better) or in the panel so the breakers will trip in the event of ground fault. As Sparky said, mark it so future users know what's up. Watch out you don't pull too much amperage and overload the feeder. If someone sees a lot of breakers in there they may think there's more capacity there than there is, and try to use it, but the generator should have breakers to prevent that. Size the feeders to the breaker in the generator.
Good luck
|
|
MtnDon
Member
|
# Posted: 22 Feb 2014 10:03am
Reply
Quoting: bldginsp I don't see how jumping the two hot legs would create any hazard so long as you have only one hot lead coming in.
Agreed, as long as you note the setup. That is done all the time in off grid situations and can even pass the electrical inspectors scrutiny if it is neat, tidy and marked.
|
|
toyota_mdt_tech
Member
|
# Posted: 22 Feb 2014 10:03am
Reply
Just put in your panel like you normally would, then on the inputs for the "line", ie the area where the 2 legs of AC 240 come in for regular service, just jump across those, ie tie them together with a large wire, large enough to handle 1/2 the the load. I'd use a piece of 6AWG wire or larger. Then hook your generator into your circuit and it will power up the entire panel and if you ever get service, remove the jumper. Everything else stays the same. 2 minute job to convert and 2 minutes to convert back.
|
|
bldginsp
Member
|
# Posted: 22 Feb 2014 02:55pm
Reply
Toyota- one disagreement- the jumper should be sized for the entire load, not half the load, because you don't know which breakers the load will be pulled off of. It could all be pulled off of one bus bar, depending.
Make sense, saskboy?
|
|
jackaxe
Member
|
# Posted: 22 Feb 2014 05:03pm
Reply
Find out the minium amperage allowed for your cabin in your area, if you were on grid. Get that size panel and do as sparky1 says. Wire one side and every other breaker is hot. Bob's not my uncle.
|
|
MtnDon
Member
|
# Posted: 22 Feb 2014 07:54pm
Reply
I am curious why some of the respondents insist that using half the panel is the way to go? The OP stated he was basically remote, not grid tied at all. IF the left and right legs of a standard panel are jumpered and the details noted on the service panel everything can be safe.
As soon as the grid is brought in the whole thing changes. At that point the service size will have a minimum; 100 amps is what the NEC calls for. There will be 240 volts as well. But that is for a normal size full time home. The OP called this a shack IIRC. I assume there are no inspections for anything. IMO, as long as the owner/builder hooks up his small system safely he is fine with the proposal. But that is just an opinion..........
|
|
|
bldginsp
Member
|
# Posted: 22 Feb 2014 08:15pm - Edited by: bldginsp
Reply
It should be pointed out that as soon as two phases are brought in the whole thing changes, not just a service. Most generators will deliver two phases, so if later a different generator with two phases, 240v is hooked up that jumper has to go. But in that case a new feeder is going to need to be installed, with two hots, so hopefully whoever does that doesn't think the jumper is a necessary part of the installation...
Since a jumper like that is a direct short between phases (if there are 2 phases) it would throw the generator breaker before the engine got up to speed. But if the generator doesn't have overcurrent protection, you'd have some interesting fireworks.   
|
|
saskboy
Member
|
# Posted: 23 Feb 2014 10:23am
Reply
Well I think for the sake of future problems im just going to install an outdoor box on the backside of the cabin, that way its 120v going into cabin, no wiring to change after the fact. Just have to change wiring at the box outside when and if the time comes. I think our old barn on the farm is wired like that even.
|
|
old243
Member
|
# Posted: 23 Feb 2014 11:08am
Reply
As far as bringing your hydro panel to the outside wall. I have seen them installed this way . You should probably build a wooden enclosure over the panel, with a sloped roof to protect from moisture.
To make best use of the panel you install, I think you would still be best to install a jumper , as previously suggested . It should be sized at the full rating of the panel. This way you can wire your cabin, properly Balancing the load , in the panel . I f you later, Do connect to a 240 volt supply . All you have to do is remove the jumper.
Your supply cable would have to be changed to 3 wire , at that time as well.
old243
|
|
MtnDon
Member
|
# Posted: 23 Feb 2014 02:11pm
Reply
Quoting: old243 You should probably build a wooden enclosure over the panel, with a sloped roof to protect from moisture.
Just buy an outdoor panel.
|
|
creeky
Member
|
# Posted: 23 Feb 2014 04:44pm
Reply
saskboy.
you can go either way. jumper or not. if you jumper (my box is jumpered) then you can have more circuits. but you still only have so many amps.
your genny only runs 120. imma guessing it's not a lot of amps. so using 1/2 of the panel reminds you that you need to keep your loads lower. so sparky1 is right on.
if you add 240 later you can run bigger loads on more circuits. it's pretty simple. so if you jumper now and add more circuits your wiring is done when you add more power (solar/genny/whatever).
if you're not planning on increasing your power input, the circuits on 1/2 a panel at 120 will more than suffice. i'm not sure of the code, but i thinks it's what. 12 lights and/or plugs per circuit?
i have 20 amps of power (solar). the reason I jumpered is so i can have 2 circuits to my studio and 1 circuit to the washroom. and I have one circuit available. small outdoor rated box. just makes it easier to turn power off/on to the various areas of my camp.
but at 20 amps of power. i'm pretty dang careful about the loads. 3 15 amp circuits run full out would trip the inverter pdq...
|
|
cbright
Member
|
# Posted: 24 Feb 2014 09:40am
Reply
FWIW, this is how my electrical is setup...
I have an old style screw in fuse panel I bought for $30 (with about 30 good fuses included).
It is wired such that only one side is hot that gives me 6 circuits to work with. I'm using 5 of them and all have 15 amp fuses.
I "borrow" power from my neighbors and have a dedicated 20amp circuit on their panel which runs about 80 feet through heavy (10 gauge welding extension cord) to my panel.
It is attached outside with a 3 prong screw lock plug, such that I can either connect to the neighbors via the extension cord or I could put my Honda EU3000i in place (same connector) if need be.
Seems like a perfectly safe setup. Either my fuses would blow if one circuit goes over 15amps or their breaker would pop if the total draw is over 20amps.
Everything is 120v led lights, a ceiling fan, window fan, standing fan, 40" led tv, stereo system. Entire draw with everything running is well below 1000w or ~8 amps.
|
|
old243
Member
|
# Posted: 24 Feb 2014 09:45am
Reply
The reason I suggested the enclosure, on an outside wall ,to protect the house panel, was the cost of the panel. Depending on the amperage rating of the panel they can get pricy, in weatherproof. You will be taking several branch circuits and your generator feeder cable out as well. depending where the panel knockouts are on the panel, you would have to have weatherproof connectors if you used a weatherproof , exposed panel. Either method will work fine. old243
|
|
|
