DIY: GROW ROOM CONTROLLER BOX WIRING NEED AN ELECTRICIANS HELP!!!

[greengiraffe]

Hey everyone so I've been reading thread after thread trying to figure out what i need to do to build and install a sub panel in my grow room. I have gathered a pretty decent amount of information on the matter, I'm just having some problems finalizing everything, so ill fill you in with what i know, and hopefully someone can help fill in the blanks for me, so here we go.

The set up I'm trying to run is 2 600W MH lights for VEG and 1 1000W HPS for flowering. All this I figure is about 10A, I also will be running a AC unit for my intake and a inline fan for my exhaust, I plan install some form of enviormental control as well, just havent quite made up my mind yet on what type. I've seen a couple DIY thermostats but it seems that half the farmers on here are for them and the other half is against them siting easy house fire as the reason, so mabye someone can clear this matter up for me. Other than those big items I'm pretty sure everything else will be fine being ran on a single pole 20A breaker. Now that everyone is caught up to speed on what the over all finished product will have to do I have some questions for you guys starting with the Main panel.

I have a 200A main breaker panel that runs the house( see pics below), I know that i need to install a feed breaker on my main panel to run to my sub panel, and to do that I need to decide on my sub panel Amp rating, but im not sure exaclty which one to choose. I want to be able to expand later on if i choose to so i was thinking of going with a 125A load center. (preferably this one because its a good price and is expandable)

http://www.homedepot.com/Electrical...splay?langId=-1&storeId=10051&catalogId=10053


MAIN PANEL




Now with all that said and pretending this 125A unit is the one I decide to use....

QUESTION 1:
WILL I HAVE TO INSTALL A 125A 2 POLE BREAKER ON MY MAIN PANEL, OR CAN I USE A SMALLER BREAKER AS MY FEED BREAKER?
QUESTION 2:
WHAT RATED WIRE WILL I HAVE TO USE TO RUN FROM MY MAIN PANEL TO THE SUB PANEL?
QUESTION 3:(THIS ONE IS GONNA MAKE ME SOUND STUPID)
CAN I PIGTAIL INTO THE EXISTING BREAKERS ON THE PANEL OR SHOULD I INSTALL A WHOLE NEW BREAKER?


SUB PANEL DIAGRAM


OK now on to the actual sub panel itself. I have made up a rough diagram of what I hope to build. I plan to initially run 2 30A 2 pole breaker for the AC and lights, and 2 or 3 15A 1 pole breakers for everything else. I also plan to install a 30A relay that will to timed, everything else will have constant power.This is the part I'm pretty confident about because I have read threw a lot of similar DIY projects, and I'm left with only these questions:

QUESTION 1:WHAT WIRE SIZE IS REQUIRED FOR THE WIRING OF THE SUB PANEL?
QUESTION 2:I READ THAT BECAUSE THIS UNIT IS A MAIN LUG I WILL HAVE TO SEPARATE THE GROUND AND NEUTRAL AND POSSIBLY LIFT IT AWAY FROM THE PANEL, IS THIS CORRECT, AND IF NOT CAN SOMEONE PLEASE EXPLAIN THE IMPORTANCE OF DOING THIS?
QUESTION 3:I PLAN TO USE ONLY 2 120 OUTLETS AND 2 240 TO START WITH, THE 2 240 OUTLETS WILL BE WIRED TO THE 30A RELAY CAN THIS BE DONE SAFELY, DUE TO THE FACT THAT THE LOAD WILL BE LESS THAT 70% OF THE BREAKER AND RELAY, OR WILL THE PLUGS HAVE TO BE ON SEPARATE CIRCUITS?

I'm waiting on my harvest before I can purchase the remaining pieces for my control box, so its not a huge rush but I would like to have it completed and installed before I start my next crop, there is going to be overlap but I would like to make it as minimal as possible. Thanks for taking the time to read this thread any and all advise would be greatly appreciated and if I missed something please don't hesitate to tell me I would rather know then not and end up burning my house down.

HAPPY HARVEST EVERYONE!!!!!

 

[BennyBlanco]

I just installed a 100amp sub panel in my grow room and i don't know dick about electric but now i do lol..but seriously i wish i would of looked into one of these before i did it though i spent the same amount of money on DIY sub panel http://www.dxhydro.com/ and i could of saved about 3 weeks worth of work

 

[greengiraffe]

Hey benny thanks for the reply! I have seen this site as well and have thought about it the only thing is im gonna end up doing a lot of the same work wether I bought a premade unit or build one myself, plus I like to learn new things makes me a better farmer

 

[BennyBlanco]

Looks like only have enough room for one breaker in n the main?
1 Yeah i would just throw a 125 amp breaker in the main
2 from the main to the sub panel i ran 12 gauge wire
3 and i would defiantly run a new beaker

But like i said no electrician

 

[greengiraffe]

Thats cool any feedback is good feedback im hoping to get a electrician's opinion nothing personal i will however look at how much a 12g wire is. I plan on taking the run under the house to the grow room im hoping to shorten the length of wire ill need some of those runs are like 100 bucks and i honestly don't have that cash right now.

 

[rives]

Let's start with what I think Benny said - if you fed your new sub-panel with #12 wire, it needs to be protected with a 20 amp breaker. Check the tables in the following link to see the amperage that various wire gauges are rated at: https://www.icmag.com/ic/showpost.php?p=2263849&postcount=1

Now back to your questions, GG. Main panel questions -

1) No, you don't have to use a breaker that is rated for the full ampacity of the sub-panel that you are using. The breaker does need to be sized to the wire that you are using to feed it with, however.

2) This depends on what capacity you want your new panel to have. For instance, if you decide to use #6 wire, it should be protected with a 60 amp breaker. Bear in mind that you need to limit the draw on circuits that are feeding continuous loads (defined as being over 3 hours in duration) to a maximum of 80% of the breaker rating. To arrive at what you need, use this formula: (1.25 x continuous load) + intermittent load = minimum breaker size. Then move up to the next standard-sized breaker, and select a wire gauge that is rated for that amperage.

3) You will need a dedicated breaker to feed the panel with, not pigtail into one supplying an existing load.

Sub-panel questions:

1) This is covered above, I think.

2) A sub-panel within the same structure as the main panel that is supplying it should have the neutrals and the grounds terminated on separate busses. The neutral buss has a jumper or long screw that can optionally be used to ground the buss to the enclosure - this should not be used in this application. The neutral and the ground should only be tied together at the main panel, or you can create "ground loops" (http://en.wikipedia.org/wiki/Ground_loop_(electricity)), which can raise hell with sensitive electronics.

3) I'm not clear on what you are asking here - if you are asking if both your 120v and your 240v loads can be fed by the same breaker, then the answer is no.

 

[MagicChef]

Looks like only have enough room for one breaker in n the main?
1 Yeah i would just throw a 125 amp breaker in the main
2 from the main to the sub panel i ran 12 gauge wire
3 and i would defiantly run a new beaker

But like i said no electrician

Are you friggin' crazy? A 12 guage wire is only good to 20 A. Then because your loads will be on for more than 3 consecutive hours, they are considered constant loads, you cannot exceed 80% of your breaker size and should size your wire accordingly...

 

[MagicChef]

oops, just read RIVES post above mine, sorry for the repeat, he said it all.....

 

[MagicChef]

It is imperative that you disconnect the little attachment bar bonding the ground and your nuetral bar AT THE SUB PANEL. At your main panel, this is left intact as you want any unbalances to go back to your main panel and drained rather than at your sub.

 

[greengiraffe]

Thanks Rives for the reply I hear ya loud and clear on everything you said. I am however wondering where I get the numbers for the intermittent load and continuous to plug into that formula? Also sorry i was writing this thread at 3 in the morning and was pretty tired so let me clarify. I plan to run four 220 outlets and four 110 outlets i guess what i was asking was if i wired it to accept 4 600w lights would a 30A breaker be sufficient, i use the standard formula to calculate amps and im way under if i used a 30A and that even considering in the under 80%, i was just seeing if my math was right.

 

[rives]

Thanks Rives for the reply I hear ya loud and clear on everything you said. I am however wondering where I get the numbers for the intermittent load and continuous to plug into that formula? Also sorry i was writing this thread at 3 in the morning and was pretty tired so let me clarify. I plan to run four 220 outlets and four 110 outlets i guess what i was asking was if i wired it to accept 4 600w lights would a 30A breaker be sufficient, i use the standard formula to calculate amps and im way under if i used a 30A and that even considering in the under 80%, i was just seeing if my math was right.

You should be able to get the load figures from the nameplates on the equipment. If it is listed in watts, divide the wattage by the voltage that you are running, and it will give you the amperage - for example, 600 watts / 240 volts = 2.5 amps or 600w / 120v = 5 amps. Remember that there are also ballast losses (the current that the ballast uses to operate), usually around 3-5%, beyond the actual lamp rating.

If you are talking about using 30 amps as a main breaker, that will handle (4) 600's, even at 120 volts, as long as the load is balanced on both phases. If you are talking about using a 30 amp breaker in the sub-panel, I would suggest breaking the circuits up to where they will run on 15 or 20 amp breakers. Remember, the breaker needs to be sized to protect the lightest component in the circuit, so if you size things to run on standard 15 or 20 amp receptacles it will be cheaper and the parts will usually be easier to find.

 

[greengiraffe]

So I attempted the math and this is what i got:

5% of 600W is 30W
630x4= 2520 Total watts (lights only)
2520/240= 10.5A well round this to 11A which is 55% of 20

At 11A I could run all four on one 20A 2P breaker but your saying it would be smarter to divide it into two 15A breakers?

 

[rives]

so 1200W/240V=5A with that in mind i could hook 4 600W ballasts up to one 20 amp 2 pole breaker? Because if you doubled it, it would be 10A which is 50%. Now with the ballast draw if your running 4 ballasts does the percentage stack? so 4 ballasts at 5% equals 20% additional draw?

Yes, a single 20 amp double-pole breaker would easily handle your (4) 600's. No, the ballast losses don't stack in the manner you describe. For instance, if a single ballast uses 5% to run, then the power going to that component would be 630 watts. 630w x 4 = 2520 watts. 2520/240=10.5 amps. Alternatively, 600w x 4 = 2400 watts, 2400*1.05=2520 watts total.

Ballast losses may range as high as 10% on lower wattage fixtures - it wouldn't be unusual to see a 400w fixture pulling 440 watts.

 

[rives]

So I attempted the math and this is what i got:

5% of 600W is 30W
630x4= 2520 Total watts (lights only)
2520/240= 10.5A well round this to 11A which is 55% of 20

At 11A I could run all four on one 20A 2P breaker but your saying it would be smarter to divide it into two 15A breakers?

No, I was referring to your post that you were talking about using a 30 amp breaker - I couldn't tell if you were planning on that as a main breaker or to feed the lighting circuit.

 

[greengiraffe]

oh oh ok well that is something i need to figure out is what size breaker i wanna install on the main panel. Now just because the loadcenter is 125A that doesnt mean i have to use that much right so i could put a 60A breaker on my panel if i can find it and then my sub panel will not be able to exceed 60A right? The 125A is just the max that its rated to right?

 

[rives]

oh oh ok well that is something i need to figure out is what size breaker i wanna install on the main panel. Now just because the loadcenter is 125A that doesnt mean i have to use that much right so i could put a 60A breaker on my panel if i can find it and then my sub panel will not be able to exceed 60A right? The 125A is just the max that its rated to right?

Yes, that is correct. Keep in mind the 80% rule, it applies to main breakers as well as individual circuits.

 

[greengiraffe]

ok thx for the imput rives