Do I have enough juice for this setup?

Hi, recently acquired a new space for my legal grow. I'm doing a 2 room design and have 50 amps available in each room. I want to run in EACH room:

4x600W HPS ~ 20 amp
1x13,000 BTU heat/air condition/humidity controller ~ 11 amp
fans + accessories ~ 5 amps


One room will have 1x15AMP 2x20AMP breakers = 55AMPS

Other room 2x15AMP 1x20 = 50AMPS


I may have some other things needing small draws. But overall, is this enough juice?

Am I to assume you plan to individually switch the hps lights on/off?

Stevie51 said:

Am I to assume you plan to individually switch the hps lights on/off?

Click to expand...

When one room has lights on, the other will be off, ya.

I am currently going through Juice problem as well. If yoru going to flip off/on manually, should be good.

Your good you just need to get a flip box.

what type is the best? what's the purpose?

Its enough amperage, but it will ultimately depend on how many watts/amps is on each 15 or 20a circuit...

A 15a circuit max wattage is 1800w [15a x 120v]....a safer loading is somewhere closer to 12-1500w max

A 20a circuit max wattage is 2400w [20a x 120v]...a safer loading is somewhere closer to 18-2000w max

4-600w Lights = 2400w so they all won't fit on any one circuit.

Nothing worse than melting wires in your walls...

Here is one arrangement that would get everything running safely..

Room A: 1-15amp and 2-20amp circuits

15amp circuit:
HVAC Unit @ 11amps
TOTAL LOAD: 11amps

#1 20amp Circuit:
2-600w lights @ 10amps
Split Accessory load @ 2-3amps
TOTAL LOAD: 12-13amps

#2 20amp Circuit:
2-600w lights @ 10amps
Split Accessory load @ 2-3amps
TOTAL LOAD: 12-13amps

Room B: 2-15amps and 1-20amp circuits
#1 15amp Circuit:
2-600w lights @ 10amps
TOTAL LOAD: 10amps

#1 15amp Circuit:
2-600w lights @ 10amps
TOTAL LOAD: 10amps

20amp Circuit:
HVAC Unit @ 11amps
Accessory loads @ 5amps
TOTAL LOAD: 16amps

Of course, depending on how the circuits are wired to which recepts will be a factor, and having the lights on separate circuits means more timers...

GrowByDesign said:

Its enough amperage, but it will ultimately depend on how many watts/amps is on each 15 or 20a circuit...

A 15a circuit max wattage is 1800w [15a x 120v]....a safer loading is somewhere closer to 12-1500w max

A 20a circuit max wattage is 2400w [20a x 120v]...a safer loading is somewhere closer to 18-2000w max

4-600w Lights = 2400w so they all won't fit on any one circuit.

Nothing worse than melting wires in your walls...

Here is one arrangement that would get everything running safely..

Room A: 1-15amp and 2-20amp circuits

15amp circuit:
HVAC Unit @ 11amps
TOTAL LOAD: 11amps

#1 20amp Circuit:
2-600w lights @ 10amps
Split Accessory load @ 2-3amps
TOTAL LOAD: 12-13amps

#2 20amp Circuit:
2-600w lights @ 10amps
Split Accessory load @ 2-3amps
TOTAL LOAD: 12-13amps

Room B: 2-15amps and 1-20amp circuits
#1 15amp Circuit:
2-600w lights @ 10amps
TOTAL LOAD: 10amps

#1 15amp Circuit:
2-600w lights @ 10amps
TOTAL LOAD: 10amps

20amp Circuit:
HVAC Unit @ 11amps
Accessory loads @ 5amps
TOTAL LOAD: 16amps

Of course, depending on how the circuits are wired to which recepts will be a factor, and having the lights on separate circuits means more timers...

Click to expand...

Thanks a lot GrowByDesign! I'm having my electrician put the 2 extra 20A circuits into room A each with their own 2 port outlets, and 1 extra 20A into room B since it already has 2 15A circuits of it's own. I understand I will need separate timers.. there's no problem with that though I assume.. I've gone through every outlet and breakers to find out exactly what the rooms had to begin with.

Glad it helps! The more I think about it the more I think I would prefer the lights in each room being on separate circuits/timers within each room....mainly as a sort of backup for any failure that may occur....the 2nd light will still be on Timers...always keep a backup ready to go!

I've got my light and exhaust fans on separate circuits/timers though they both run the same 12/12 cycle...just takes a bit of tweeking to get them in sync is all.

Someone insists I wire up a 220 circuit to each room enough to run 4x1000W HPS. Is it possible to run two of these 220 circuits to each room? how many amps should I have each circuit use (double pole breaker type?) ... I want to be running the 1000's from 220 instead of 110... does anyone do this? thanks

to size a breaker...

total watts divided by voltage used equals amps...pad 4-5amps and round up.

a 1000w 240v light is going to draw 4.3 amps x 4 lites = 16.6 amps

a 2p-20a 120/240v breaker should be plently....I'm not an electrician, just a codes guy.

I have no idea if people do it....I'd think so for larger ops just to be able to minimize breakers.

GrowByDesign said:

to size a breaker...

total watts divided by voltage used equals amps...pad 4-5amps and round up.

a 1000w 240v light is going to draw 4.3 amps x 4 lites = 16.6 amps

a 2p-20a 120/240v breaker should be plently....I'm not an electrician, just a codes guy.

I have no idea if people do it....I'd think so for larger ops just to be able to minimize breakers.

Click to expand...

A codes guy would rather we use nameplate values. All ballasts have losses via heat. At 240v a 1kW might pull more like 5 amps.

Your 16.8 amps would trip a 20a breaker as it's past the 80% threshold. Continuous loads need to be rated at 125%.

A two pole puts us at 240v and he can't run other loads on that feed.

I just really need to figure out what I want added to these 2 rooms and still be ok. Was doing some thinking last night... why am I just going to put in 3 more circuits.


I can have both rooms setup to handle 70-80A, 3x 20A extra circuit per room. At any given point, the most I will have on is 4x1000W's, they turn off and the others fire up.. as long as I keep my lights on schedule and never have 8 lights + all equipment running at once I should never come close to tripping the floors 100A main, right?

maybe one of these would help
https://www.sunlightsupply.com/shop/bycategory/environmental-controllers/titan-controls-helios-11

SnapsProvolone said:

A codes guy would rather we use nameplate values. All ballasts have losses via heat. At 240v a 1kW might pull more like 5 amps.

Your 16.8 amps would trip a 20a breaker as it's past the 80% threshold. Continuous loads need to be rated at 125%.

A two pole puts us at 240v and he can't run other loads on that feed.

Click to expand...

No, a codes guy likes to cover his ass...OP is putting 4 lites in each room divided between 2 circuits....2 rooms, 4 circuits, 8 lights...

He did say he was putting TWO 240v circuits in each room, and as we had already discussed having lites within each room wired separately and on separate circuits I am assuming that as a given...we're talking two lites on each breaker, within each room...not one breaker for all lites within each room...

that sounds to me like a roughly 9a load per circuit...but I'll do the math...

8000w / 240v = 33.3a / 4 [ckts] = 8.3a per circuit...check.

20a 2-pole breaker...8.3a load...check. [I'm not onsite, or in charge and able to forego any stupidity so screw 125%...Im covering my ass! ]

and...I guess I shouldn't assume it is a known that the two poles of each breaker are slaved w a switch bar or you'll just have 2-20a 120v circuits...

As for running other loads as well...he only stated he would be running the lights on the 240v lines and he didn't state any changes to previously discussed 120v circuits...I can't factor what I haven't been asked to...

I would certainly defer to your experience regarding light-specific operations like heat/amperage increases and consider that as well...

1000w @ 5amps X 8 = 40amp total load / 4 [ckts] = 10a per circuit...still at 150% demand, or am I missing something here?

fuzzyl said:

I just really need to figure out what I want added to these 2 rooms and still be ok. Was doing some thinking last night... why am I just going to put in 3 more circuits.


I can have both rooms setup to handle 70-80A, 3x 20A extra circuit per room. At any given point, the most I will have on is 4x1000W's, they turn off and the others fire up.. as long as I keep my lights on schedule and never have 8 lights + all equipment running at once I should never come close to tripping the floors 100A main, right?

Click to expand...

Well, when you mentioned running new 240v lines I started wondering why it seemed like you were still trying to "make do" with amperage...if you are just going to re-wire do it right and give yourself the juice you need now and in the future...jmo

Your suggested method of operation, while 'feasible'...again is rather impractical given that you are going to re-wire, personally it sounds like a recipe for trouble.

It really sounds like you need to sit down and think about exactly what you want to see when the dust settles...do some load demand calcs and size your electrical system based around it and then build...again jmo

Problem is I'm strapped for time a little bit, only a few more weeks until I get my new location. It wasn't easy to find a location in which I know the landlord and is letting me bring a electrician in.

I just spoke to my elec. he's recommending I have him run 2x 30A double pole 240 line with 10-3 10 gauge wire - one circuit per room. Both circuit hooked up to Titan Helios 4 controllers 1 per room. That covers the lights. He will then run another 2 120V dedicated circuits one per room which will we will have the AC system on. The existing circuits in the room will power oscillating fans, and small accessories.

Remember at any point only 4x1000 is going to be powered on. I'm not worried about using more elec. than the place supports.

fuzzyl said:

Problem is I'm strapped for time a little bit, only a few more weeks until I get my new location. It wasn't easy to find a location in which I know the landlord and is letting me bring a electrician in.

I just spoke to my elec. he's recommending I have him run 2x 30A double pole 240 line with 10-3 10 gauge wire - one circuit per room. Both circuit hooked up to Titan Helios 4 controllers 1 per room. That covers the lights. He will then run another 2 120V dedicated circuits one per room which will we will have the AC system on. The existing circuits in the room will power oscillating fans, and small accessories.

Remember at any point only 4x1000 is going to be powered on. I'm not worried about using more elec. than the place supports.

Click to expand...

Your electrician has it right. I would go with that.

fuzzyl said:

Problem is I'm strapped for time a little bit, only a few more weeks until I get my new location. It wasn't easy to find a location in which I know the landlord and is letting me bring a electrician in.I just spoke to my elec. he's recommending I have him run 2x 30A double pole 240 line with 10-3 10 gauge wire - one circuit per room. Both circuit hooked up to Titan Helios 4 controllers 1 per room. That covers the lights. He will then run another 2 120V dedicated circuits one per room which will we will have the AC system on. The existing circuits in the room will power oscillating fans, and small accessories.Remember at any point only 4x1000 is going to be powered on. I'm not worried about using more elec. than the place supports.

Click to expand...

4000 watts at 240 you want to run 30 amp breaker minimum is what my electrician buddy says.

fuzzyl said:

Problem is I'm strapped for time a little bit, only a few more weeks until I get my new location. It wasn't easy to find a location in which I know the landlord and is letting me bring a electrician in.

I just spoke to my elec. he's recommending I have him run 2x 30A double pole 240 line with 10-3 10 gauge wire - one circuit per room. Both circuit hooked up to Titan Helios 4 controllers 1 per room. That covers the lights. He will then run another 2 120V dedicated circuits one per room which will we will have the AC system on. The existing circuits in the room will power oscillating fans, and small accessories.

Remember at any point only 4x1000 is going to be powered on. I'm not worried about using more elec. than the place supports.

Click to expand...

That sounds like an excellent plan, and the bonus of having your grow rooms lighting on 240 volts is that it ensures that the lighting load remain balanced to your main panel. Using a lighting controller make good practical sense to switch the lighting on/off in my opinion.