All kinda of Electrical questions...?

[Blunted22]

Ok guys im wiring up a new house and im trying to get everything upstairs. i currently have 60 amps ran upstairs on plugs. Im useing 2 rooms up there one for flower (14x10) and one for veg (6x10). Heres the first question...

1) i got a sparky to run 2 more 20 amps from the box to the upstairs. Problem is he ran them to wrong room. So im running them out of this room down the hall and hadwire them to new plugs in my grow room. The wierd thing is (and i could be totally wrong) i thought i would see different set of wires for each 20amp breaker but he used one. We used a 12x3 600 volt wire. and he basically used the same ground and same negatives for both plugs and different positives for each plug. Im just concerned if we maxed out the amperage of both breakers useing 1 wire will it be safe? ( i know you can only run 80% anyways)

2) If i need antoehr 20 amp breaker for power can i steal the power from my upstairs lights? Lets say one 20a breaker is ran to only my upstairs lights (3 60w lgihts) Can i like pull out a fixture and tie into that safley and add a plug to be on another breaker for more amps for the upstairs? Is that possible/safe. The house wireing is kinda old but the box is semi upgraded.

 

[Guest]

What the electrician did was run a 3 wire with a shared neutral to power two seperate circuits,its quite common in wiring procedures.He does have them on seperate 20A breakers correct?If so you can draw 16A on each circuit providing the neutral wire is also #12 and I'm sure it is.The neutral will carry the unbalanced load,so if you're drawing 16A one 1 circuit and 0A on the other,the neutral will carry 16A.You must have a 12 wire neutral to carry the possible unbalanced load.EDIT To be more clear if 1 circuit is drawing 16A and the other is drawing 16A the load on the noodle is 0A.If circuit A is drawing 10A and circuit B is drawing 5A the load on the noodle is 5A.

 

[Blunted22]

thanks american yes its a 12 3 neutral. What about that 2nd question?

 

[Blunted22]

bump bumpity bump

 

[screwdriver]

What the electrician did was run a 3 wire with a shared neutral to power two seperate circuits,its quite common in wiring procedures.He does have them on seperate 20A breakers correct?If so you can draw 16A on each circuit providing the neutral wire is also #12 and I'm sure it is.The neutral will carry the unbalanced load,so if you're drawing 16A one 1 circuit and 0A on the other,the neutral will carry 16A.You must have a 12 wire neutral to carry the possible unbalanced load.EDIT To be more clear if 1 circuit is drawing 16A and the other is drawing 16A the load on the noodle is 0A.If circuit A is drawing 10A and circuit B is drawing 5A the load on the noodle is 5A.

Whoa.....I am not an electrician. I have seen that practice of using 12/3. I don't believe the current cancels out like that please explain further. I could run my whole house like that and cut my electric bill ? Its a bad practice IMO.

 

[Guest]

It's electrical 101 bro,the neutral always carries the unbalanced load.The formula for 3 phase is more involved but I run 12/4 utilizing 3 seperate circuits sharing the same neutral as a matter of course,at least I use to before discovering overgrow lol.With single phase its really simple,the neutral will carry any difference in load between the two hot legs,its where the term "balanced panel" comes from.Note these circuits must be on there own breakers,if you use a 2 pole breaker for 2 circuits sharing a neutral and one circuits trips,you lose both circuits.Starting from the top left breaker and working down it goes A-B-A-B-A-B etc and each leg is connected to a seperate 120V busbar.What you shoot for when wiring a panel is total load on A =total load on B,this is a perfectly balanced panel and a fantasy lol,the idea is to keep it close as to not overload the neutral.I've seen commercial panels where the service neutral is hot to the touch because of major imbalancing.Blunted short of rerouting that lighting circuit to your desired location or running another circuit from the panel,you dont have many good options.You could mount a wiremold box where the light is and run wiremold raceway to your desired location but that has a drawbacks,work being the biggest lol.You may experience voltage drop if the run is too far and I have a hard time believing that light is on a dedicated circuit.If the house is wired properly there are probably many lights in different rooms on that same circuit,you want to keep lighting and power circuits seperate.Otherwise you plug in your blowdryer and your lights go dim lol.So putting a heavy load on a lighting circuit will undoubtedly cause a lot of other household lamps to burn dim

 

[MajLeeStoned]

....load on the noodle is 5A.

ouch, my aching noodle is not rated that high.

OMFG when I read that I busted out laughing at 6 in the AM. Thank-you American. Oh I'm so buzzed.

Wake-N-Bake

 

[Guest]

Some people think they can't be shocked by a noodle,they've never seen mine lol!

 

[cocktail frank]

Whoa.....I am not an electrician. I have seen that practice of using 12/3. I don't believe the current cancels out like that please explain further. I could run my whole house like that and cut my electric bill ? Its a bad practice IMO.

bad practice? i think not.
you obviously aren't a sparky.
like american said, you can share a neutral on branch circuits, but only up to as many poles as you have.
2 pole, 1 neutral, residential service 220/110v
3 pole, 1 neutral, 3 phase, commercial/industrial 480/277v, 208/120v
BUT, you can only share that neutral if its ran in the same wire/pipe, otherwise you'll get all sorts of heat problems and other tech stuff i feel i dont need to go into detail about, because it doesn't apply here.
it wont help you save on you electric bill running 3 wire like that, but it could help you evenly balance the loads on your phases.
which in turn means you run more efficient, which in some areas can actually save you a few bucks.

 

[Guest]

Good point cocktail frank,always place your noodle in the correct pipe otherwise you can run into problems I feel I don't need to go into detail about lol.

 

[Blunted22]

Hey american no one lives in that house as i stated above their is a 20a circuit for the 4 upstair lights which i wont use if i can change it to a plug but it didnt sound that simple in your explination so that might not be an option.

Im guessing its different wireing for a light then a plug that could hold the whole 17-18a safely. So my option would have to be rerun a new wire from the breaker box?

 

[Bulldog11]

As for question #2, you should find out what the max draw is on the existing curciut. Then add up the max draw on your new equipment you want to add to the curciut. If the total amps are 80% of the curciut breakers total amps then you COULD do this. I however would run a new curciut and not worry about it, you don't want wierd issues with your lights like flickering or diming. For future knowledge, it would have been easy to have the sparky install a sub pannel upstairs for you so you could pull as many curciuts as needed. Accounts for future growth also.

 

[Bulldog11]

20a could hold 16a of continous power, period. As for wiring up from a switch is a little different, however easy to find where the power comes from. Take off the switch (single pole) and disconnect the wires. There should be two black wire, one will be the constant power. Use a tester to find which wire is hot. From there follow back to junction box or make switch box junction box. Once you found the hot side of the switch you will just connect your new wires black to black, w to w and g to g. Presto chango, you now have hot plugs.

 

[Guest]

Got an attic in there?Find the circuit supplying the 4 lights,cut it at the nearest point to your new outlet location,put in a juction box and run 12/2 with ground to your outlet.Easy if you have room in your attic.Drill a hole in the ceiling joist,cut a hole in the wall for your receptacle box,and drop the wire down the wall.If its insulated you have to fish it,no big deal.If you never plan on using the lights thats what I'd do.No having to drop a circuit into an existing residential panel which can be a bitch somtimes,your circuit is already there tied in to your breaker and everything.One thing,most lighting circuits in homes are #14 AWG,make sure some genius didnt slap 14 wire on a 20 amp breaker,it must be 12 to carry 16A continuously

 

[Ganoderma]

he basically used the same ground and same negatives for both plugs and different positives for each plug. Im just concerned if we maxed out the amperage of both breakers useing 1 wire will it be safe? ( i know you can only run 80% anyways)

the reason that you can use one neutral wire and one ground is, you have AC current, which is alternating current, with a home you have two legs like was stated above some where(A-B-A-B-A-B), those two legs are 180 degrees out of phase from each other. just think about one of those old steam powered train engines, the piston on the left is pushed out(the one on the right is pulled back in), then the piston on the right is pushed out (and the left on is pulled back in) you see the cycle that continues, this is how AC power works in your house (I'm only talking about in homes, and won't go into commercial/3phase as this is not what was asked) so the power cycles back and forth so with you set-up with a 12-3 wire with two breakers, if you have 15amps on one and 12amps you only have one of those on the neutral wire at one time. So it doesn't add up to cause and over load on the neutral.

now if you wont to place a GFCI(GFI as sparkys call them) on both of those curcuits you'd have to have two neutral's as the GFI's would trip each other

 

[Blunted22]

thanks guys i get it enough now ill idnt install a subpanel cause its not a perm setup its only a simple setup till we find the perfect house.