Rewiring Oven outlet for grow room, need help.

[brutzuk]

Hello all, have a question or two and hoping i can find answers here.

Ive done this before, but after reading the electricity thread stickied here it got me thinking. At my last place the oven outlet was on a 40 amp breaker, 240 volts. I rewired it into 120 volts with around 8 outlets, and I was running about 3600 watts through these outlets, the wire was 12 gauge. Never had any issues.

My new place the oven is on a 50 amp breaker. i plan on doing the same thing. But after reading that stickied thread, it said that for 12 gauge wire you shouldnt be running any more then 1900 watts through it?! How is that possible if I was running double that with no problems for a year straight?

Advice welcomed, thanks.

 

[brutzuk]

Also my run is about 15-20 ft and I have the 25ft wire. 12/3, would that be ok or would I be required to go with 10/3?

 

[rives]

12 gauge wire is rated for 20 amps, which would be 2400 watts. The 1900 watts comes from the breaker rating. For continuous loads, which are considered to be anything over 3 hours duration, you are only supposed to use 80% of the breaker rating. 80% of 2400 is 1920 watts.

As to how how you got away with it for so long, part of it may be related to how you "re-wired" it to 120. 240v is 2 legs of 120, so if the load was evenly split between the 2 legs, you would have had 1800 watts on each and still had used 120v exclusively. If that isn't what happened, it may have been due to the ability of a short length of wire's ability to carry considerably more amperage than it is rated for. It may also have been that you were just very lucky.

*edit* - Just saw your second post. #12 wire is rated for 20 amps, #10 is for 30 amps. A 50 amp breaker is going to require #6 wire.

 

[RubeGoldberg]

Why not just grab a length of oven cable from home depot and run a subpanel off the oven outlet? then at least you have a modular setup you can take with you when you leave.

 

[brutzuk]

^^Hmm that sounds like a great idea. The problem is my buddy is the electrician who does all this for me, so I really dont know whats going on, but if I were to do that, how would I convert the 240 into 120? Through the subpanel?

Also is it easier to rewire the outlet, or straight from the breaker/panel itself? Whats more cost efficient?

 

[rives]

^^Hmm that sounds like a great idea. The problem is my buddy is the electrician who does all this for me, so I really dont know whats going on, but if I were to do that, how would I convert the 240 into 120? Through the subpanel?

Also is it easier to rewire the outlet, or straight from the breaker/panel itself? Whats more cost efficient?

An oven receptacle should be 120/240 - there should be 4 prongs on the plug. (2) 120v leads, (1) neutral, and (1) ground. This can be fed straight into a 120/240 subpanel, and then breakers set in the sub to distribute both 120 and 240 if needed. Home Depot should have pre-made range cords with a plug already installed - just make sure that the configuration is the same as your receptacle.

 

[brutzuk]

ok Yeah that makes sense, yeah the plug has 4 prongs. Last time i did this we just ran the wire right into the grow room, and plugged it right into 15 amp outlets. So this was extremely dangerous? lol. Roughly how much would a 120/240 subpanel cost me?

Also again is it easier to rewire straight from the breaker/panel? The panel is actually in my grow room, so if this is easier.. Just trying to set up 8 15 amp 120v outlets as easy and cost efficient as possible, also being safe, from the 50 amp breaker or 240 outlet.

 

[RubeGoldberg]

^^Hmm that sounds like a great idea. The problem is my buddy is the electrician who does all this for me, so I really dont know whats going on, but if I were to do that, how would I convert the 240 into 120? Through the subpanel?

Also is it easier to rewire the outlet, or straight from the breaker/panel itself? Whats more cost efficient?

basically, you'll have 2 hot wires of 120, so you just split them in to their own clusters of outlets on the subpanel which will be at 120.


Whats the reason for running the ballasts on 120?

 

[RubeGoldberg]

ok Yeah that makes sense, yeah the plug has 4 prongs. Last time i did this we just ran the wire right into the grow room, and plugged it right into 15 amp outlets. So this was extremely dangerous? lol. Roughly how much would a 120/240 subpanel cost me?

Also again is it easier to rewire straight from the breaker/panel? The panel is actually in my grow room, so if this is easier.. Just trying to set up 8 15 amp 120v outlets as easy and cost efficient as possible, also being safe, from the 50 amp breaker or 240 outlet.

If your panel is in the grow room, its easier to just put in a new breaker and run your grow room needs right from the panel.

I've been compiling a video of breaker installs on diff types of panels over the past few months, I'll try to remember to upload it today.

So long as your house's total amperage can handle it though, a new breaker will likely be your safest bet.

The oven outlet is nice, but if you're running extra wiring its a hassle.

 

[rives]

If you have breaker space in your existing panel, you can set additional breakers to feed your receptacles. If not, then you could either feed a sub straight off of the 50 amp breaker or from the oven receptacle. You have to have additional 15 or 20 amp breakers protecting the 120v outlets. Subs start at about $15 and go up. Cheap safety.

 

[brutzuk]

Ok so looks like im going to be running a subpanel from the 50 amp breaker. home depot has 70-125 amp sub panels, which Im guessing Im fine going with a 70 amp correct.. since it just means max usage. Then I can run my outlets from the sub panel..

I would run 240 but my ballasts are already 120 plugs, which wouldnt be that big of a deal i would go buy 240 plugs but my portable AC is 120 as well.. as well as my fans and pumps etc.. everything I have is 120.. so to convert it all to 240 would be a pain.

So.. hopefully I can get a hold of my bud soon to come check this out.. but how exactly does one go about wiring a sub panel off a 50 amp breaker?

 

[Floridian]

sub panel

sub panel

Your two colored wires go into the main lugs your noodle on the neutral bar and the ground should bond to the panel with appropriate screw or lug.Your neutral and ground should have no continuity at the subpanel

 

[qupee]

Your two colored wires go into the main lugs your noodle on the neutral bar and the ground should bond to the panel with appropriate screw or lug.Your neutral and ground should have no continuity at the subpanel

Yep, it's really simple. 4 wires. hook up the panel from the oven outlet feed like Floridian explains then pop in a breaker and take your hot off that and neutral & ground off their respective bars to run a string of outlets.

I have a QO 100A 8 space/16 circuit panel was like $35 plus $5 for the ground bar kit at Depot. Nice little box.

 

[RubeGoldberg]

Ok so looks like im going to be running a subpanel from the 50 amp breaker. home depot has 70-125 amp sub panels, which Im guessing Im fine going with a 70 amp correct.. since it just means max usage. Then I can run my outlets from the sub panel..

I would run 240 but my ballasts are already 120 plugs, which wouldnt be that big of a deal i would go buy 240 plugs but my portable AC is 120 as well.. as well as my fans and pumps etc.. everything I have is 120.. so to convert it all to 240 would be a pain.

So.. hopefully I can get a hold of my bud soon to come check this out.. but how exactly does one go about wiring a sub panel off a 50 amp breaker?

**rubegoldberg doesnt take responsibility for this guy's house burning down**

that text absolves me of of legal issues... hahaha

seriously though you can run 240 on 120 plugs so long as the wiring can handle it, honestly, its way better, less ballast noise on core/coil ballasts and less heat/ along with running more on your amperage.

 

[yerboyblue]

looks like you got a lot of answers, but 240 50A is 6ga wire, 40A is 8ga

 

[brutzuk]

Ya thanks for the help guys. I went to depot yesterday and bought everything to do the job, and my buddy is coming over today to install it. I bought a 100 amp sub panel 6 slots. For now hook up 4 outlets of 15 amps. I have 6 gauge wire to hook up the panel to the subpanel.

Can't believe in my years of growing I never did this before lol, seems like a must have for grow rooms, I really like it too because I can expand whenever.. In the near future ill probably be switching all my ballasts to 240, which I was wondering last night glad I remembered now to ask, what is the lowest amp rating for 240 outlets? Can you run say 20 amps on 240? 30 amps? Or does it need to be 40 amps and above?

 

[rives]

**rubegoldberg doesnt take responsibility for this guy's house burning down**

that text absolves me of of legal issues... hahaha

seriously though you can run 240 on 120 plugs so long as the wiring can handle it, honestly, its way better, less ballast noise on core/coil ballasts and less heat/ along with running more on your amperage.

Jesus, Rube! While I agree that 240 is potentially a better way to go, putting 240 on 120v plugs/receptacles sure as hell isn't! If you are going to go that route, make the big investment of about $6 per cord cap or receptacle and do it correctly. Leaving traps around for yourself has never appealed to me, particularly since it can void your insurance policy. Stick with code and NEMA standards and you will have a safe installation.

 

[rives]

In the near future ill probably be switching all my ballasts to 240, which I was wondering last night glad I remembered now to ask, what is the lowest amp rating for 240 outlets? Can you run say 20 amps on 240? 30 amps? Or does it need to be 40 amps and above?

NEMA 6-15 receptacles are 15 amp, 240v components.

 

[Floridian]

receptacles

receptacles

Rives is right for sure,that being said there is no reason it wont work,I do it but had the rceptacles handy and was too lazy to get cordcaps lol.It'll work electrically,what wont work is the stoners brain when he decides to vacuum the growroom floor!