Growroom Electricity and Wiring

madpenguin · Nov 24, 2009

richyrich said:
Gotcha. Yeah, I have individual conductors ran through conduit the entire way to the sub-panel in a detached garage. Thanks.

Oh.... Technically you need to backfeed a breaker for a main disconnect if it's in detached garage. You can do it or not but detached structures fed from the main need to have a disconnect on the outside of the building or immediately inside the building.

@chongsbuddy, try not to double post. You've already started a new thread for it so there is no reason to post it here.

chongsbuddy · Nov 24, 2009

yeah sorry,i was not getting answers and i thought maybe i butted into an existing conversation.my bad.

FreezerBoy · Nov 24, 2009

madpenguin said:
That's a tough call.

In that case, I'll just leave them on. Thanks for your time and effort.

madpenguin · Nov 25, 2009

Yea, I'd probably leave it the way it was. Those conductors coming from the lamp socket could be industrial grade high temp wires along with having an outer braid.

Then again, there's really no harm in trying. As long as you check on them every so often. The first generation romex from the 50's used a lower temp insulation on the individual conductors. Just about every light fixture I've pulled down from that era has had bone dry conductor insulation that cracks and falls right off when you go to move the conductors. That's just from a 75w or 100w light bulb decade after decade of on/off/on/off.

Up to you. Looks like your only going to be able to raise it an inch or so anyway by removing that conduit body. Is that your ultimate goal? To raise the light just a little higher?

FreezerBoy · Nov 26, 2009

madpenguin said:
Is that your ultimate goal? To raise the light just a little higher?

The hood and cab are nearly identical in depth. It makes closing the door a job, I have to work at it.

Hood is banked on all 4 sides internally but, outside it's square in the back. I want to remove the junction box, move the spaghetti into the unused triangular space and run the cord out the top.

intlplayr · Nov 27, 2009

Awesome thread thanks for starting this!

One quick question to ya'll electrical geniuses. How bad is it to change out a 15 amp breaker to 20 amp breaker and then proceed to run about 18 amps off it if the original wiring was originally meant for only 15 amps. I realize it's a fire hazard but I'm trying to get a realistic view on how bad of one it presents. The building is brand new and the wiring is brand new.

I was thinking maybe as an alternative I could buy some wire actually meant for 20 amps and then wire them right from the breaker so I don't even need to run it through that skimpy wire that's in the walls, but the receptacle is nice to use and I haven't had any problems so far...

What do you think?

madpenguin · Nov 28, 2009

I think you should use your head. :abduct:

Common sense should tell you that's not the brightest of things to do.

To answer your question, the conductor insulation will deteriorate over time due to excessive heat. How much time? It's hard to say. Keep going like that indefinitely, and I guarantee you'll start a fire. It's just a matter of when, not if.

intlplayr · Nov 28, 2009

Haha ya, you're right and it does. Thanks so much for providing that for me an accurate unbiased description of what would happen. Can u believe it took me a while to get one of those?

Muchos gracias...

U da man!

rooted · Nov 28, 2009

whatup tokers :wave:

i'm in need of some guidance, any advice is much appreciated

simply put: "have 30a dryer outlet, need 30a subpanel"

can this be safely done? can it be run from a dryer plug for quick disconnect?

i've read a lot into wiring this subpanel but would like to run it by you guys first. it seems safer than the DIY 4 light controller. i built a 4 lamp flip a couple years ago that i still use in my veg room, so i feel like this is a logical next step for me, as far as DIY goes

pretty basic... just need 4 outlets (240) for ballasts, and a 120 circuit for fans

thanks

madpenguin · Nov 28, 2009

Yea, this can be done very easily. What you'll wind up with is one of those light controllers that they sell for hundreds of dollars only you'll pay just a fraction of the cost in making your own.

Read the post in this thread about how to wire up a sub panel and that will tell you how to make the correct connections for that. Get a 30A dryer cord from lowes or home depot and a larger NM connector. Buy a 3-4 space sub panel, will probably be rated at 70A.

Shit. Maybe I'll run to lowes today, make a DIY tutorial and then return everything when I'm done. But there has to be similar threads around here somewhere.

If anyone has a link to one feel free to post it. I need to rent an industrial drain snake from Lowes today anyway so if I have enough funds maybe I'll buy the parts and make a step by step tutorial.

rooted · Nov 29, 2009

that would be fuckin sick pengiun. quite ambitious you are

so to be perfectly clear, there are no obvious safety issues with running a sub off a dryer plug?

i would prefer the sub mounted inside the flower room, is this what you're suggesting? it's going to take 25ft of cord to make it there from the dryer outlet.

thanks for your help bro, wish i could pass you this bowl of afgoo

madpenguin · Nov 29, 2009

rooted said:
so to be perfectly clear, there are no obvious safety issues with running a sub off a dryer plug?

Nope. None at all. It's the same thing these hydro shops are selling for $300 - $500. As long as you affix your receptacle boxes to the subpanel itself, then everything is cord-and-plug and is not considered premise wiring. We use these in the field quite often. Most call them spider boxes.

i would prefer the sub mounted inside the flower room, is this what you're suggesting? it's going to take 25ft of cord to make it there from the dryer outlet.

That complicates things slightly. How and where is the cord plugged into the dryer receptacle going to make it to your grow room? Running through a doorway or two and laying on the floor?

There are some safety issues with that as well as it being rather conspicuous. If you can keep the cable out of harms way, then you could probably use 25' of 10/3 MC cable. Find the post here on NEMA receptacles and get your self a plug to hardwire on one end and then terminate the other end in the subpanel just like the post here in this sticky describes.

The completely square gray powder coat finish bell boxes intended for outdoor use attach to the knockouts of the sub quite well by using a metal NM connector. Just don't use the lock ring. Or you can use the standard handy boxes that you typically find on a basement wall.

Get a Main Lug Only panel instead of a Main Breaker panel. Since it's not premise wiring the cord-and-plug is allowed to be your disconnect means. Or you could backfeed a 30A Double pole breaker in the MLO panel if it made you feel any better. If you want to stay on the cool side with your wiring, make sure the cord that feeds the sub doesn't see more than 24A (80% continuous load rating)

rooted · Nov 29, 2009

sounds good penguin :yes:

i'll go do some shopping later after i get some sleep

the cord will go across the hall on the ceiling, won't be laying on the ground at all....won't be hidden either but i'm not worried about someone seeing it.

i always stick to the 80% rule, and it will be plenty

i would like to use a relay for the 240 outlets, SPST right?

madpenguin · Nov 29, 2009

No, kill both hots at once.

robbiedublu · Nov 29, 2009

Here's a question for all of you electricians. I bought a non contact current/voltage tester and I'm not sure I understand what they mean by current vs voltage.

madpenguin · Nov 30, 2009

Who's they? Not sure I know what your talking about.

What did "they" say about current vs voltage?

Those idiot testers or aka widowmakers pick up the electromagnetic field given off by the wire.

robbiedublu · Nov 30, 2009

madpenguin said:
Who's they? Not sure I know what your talking about.

What did "they" say about current vs voltage?

Those idiot testers or aka widowmakers pick up the electromagnetic field given off by the wire.

There're 2 settings on the meter. You push the button to one side to test for "current" and the opposite way to test for "voltage". Just pick one of the meters up at a hardware store and look at it and you'll see what I mean.

madpenguin · Nov 30, 2009

Oh... Weird. I'll have to look for them. Never heard of such a thing. Usually, you just see the greenlee and ideal idiot testers. Those just pick up on the magnetic field that the wire puts off if it's hot.

rooted · Dec 2, 2009

i have some questions/concerns about my dryer circuit. it has a 3 prong outlet, fed with 3 wires plus bare ground (bent back up into conduit). at the main: neutral and ground bars are stacked on top of one another

1. does that sound ok/normal for an older house?
2. the ground and neutral are not to be connected anywhere except the main panel, correct?
3. can i replace the outlet with a 4-prong using the existing wiring?
4. will i be still able to run a 120 circuit from this sub?

got a 125a mlo panel, 25' of 10/3, sockets and boxes, and a dryer plug ready to be carefully slapped together but i want to double check everything and be as solid and safe as possible considering this is a rental and i'm on a tight budget

thanks for all the help! :joint:

madpenguin · Dec 2, 2009

rooted said:
i have some questions/concerns about my dryer circuit. it has a 3 prong outlet, fed with 3 wires plus bare ground (bent back up into conduit). at the main: neutral and ground bars are stacked on top of one another

1. does that sound ok/normal for an older house?

yep.

2. the ground and neutral are not to be connected anywhere except the main panel, correct?

yep

3. can i replace the outlet with a 4-prong using the existing wiring?

yep. Use a NEMA 14-30R

4. will i be still able to run a 120 circuit from this sub?

yep.

got a 125a mlo panel, 25' of 10/3, sockets and boxes, and a dryer plug ready to be carefully slapped together but i want to double check everything and be as solid and safe as possible considering this is a rental and i'm on a tight budget

Obviously, don't use your standard 3 prong dryer plug if your going to use a 4 prong receptacle. Safety/code wise, you'll need to use a 4 prong NEMA 14-30 Receptacle and then attach a matching 14-30 plug on the end of your 10/3.... X and Y are for the 2 hots. W is the neutral and G is the ground (receptacle markings).

You should get the neutral and ground on their own terminal screws back at the main. It's a nitpicky code thing but won't affect the overall safety of the circuit if you leave them as is. One neutral per screw and no more than 2 grounds per screw is what the NEC says.

Terminate your portable sub as per the directions here in this sticky (neutrals and grounds isolated).

Your plan is sound and safe. Just make sure that romex doesn't get damaged. I'd prefer if people were to use 10/3 MC cable for these types of applications. Still easy to damage but not quite as easy as romex....

As a general rule, you should also avoid stranded wire for your termination points.

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