Please Double check my Wiring plan

[thcrefugee]

Hello, Thanks for stopping in!
After lots of reading and research, it seems I will build a subpanel/ relay board.
I have a detached garage 55 ft away with existing lights and wiring. I need more power and want to leave existing as is.
I plan to run 3 wire plus ground 10awg THHN in conduit to the garage from a 30 amp breaker in main panel.
I want to power 2 1000w lights for flower, and 1 600w for veg. on different time schedules obviously. Plus some misc fans/pumps etc.

big question is can I power 2 different relays (1 for veg, 1 for flower) from the same breaker. and will a 20amp (240v) breaker cover it. (12amps total right?) Or, should i just get the bigger box and another breaker to supply veg and flower seperate?

Also can i trigger the 240v relays with the same subpanels 120V?

added points, Do I need to drive a grounding stake if im running a ground in the feed from the main panel?

rough drawing.

Thanks!

 

[thcrefugee]

After more reading,
It appears that to use the 20amp breaker feeding the 30A relay, ill still be protected to 20 amps at the (20amp rated) outlet.
However, in planning for future adaptability (the reason for the 30amp relay) {i would like to run 3-4 lights on this in the future}.. so the supply to the relay would be a 30amp breaker
...It appears i should have a 15/ or 20A breaker/ fuse between the relay and the outlets..
It also appears almost none of the controllers on the market provide this..

Can someone shed some light on this for me too?

am i correct in saying.. Im good as long as i power the relays with a 20amp breaker, and use 20 amp outlets downstream. Once i go to 30 amp breaker supplying the relay, and power more lights in the setup.. I should put a breaker/fuse between relay and outlets?

 

[FireIn.TheSky]

You are seriously over complicating it.


All of your lights only equal 10.8 amps @ 240v.

You run 1 240v 20 amp circuit to a box, divide that circuit to another box, use 2 plug in timers, thats done.

Now run 1, 15 amp circuit to the veg area, with a plug in timer and thats done.

You can safely consume 24 amps on a 30 amp breaker.

What I do not see is your plan for misc fans, vacuums, pumps etc.. you should work in a 120v circuit in there somewhere.

By over complicating things with relays you are really risking messing something up. If you don't know what you are doing keep it simple the less wiring/wiring connections the better.

 

[rives]

First, having multiple sources going into a structure can create a scary situation when trying to shut off the power and is prohibited by code except for a handful of exceptions (fire pump power, emergency power, etc). If someone doesn't realize that there are different feeds supplying the area, they can shut off what they think is the power source and there will still be hot circuits in the building, potentially creating a lethal hazard.

Yes, you can run 2 (or many more) relays downstream of a single breaker. The 80% rule will apply to the breaker, meaning that any continuous load (any load that runs for 3+ hours) has to stay at or below 80% of the breaker rating. In the case of a 20a breaker, that means that the continuous loads need to be 16a or less, but short-term loads can bump up to the full rating of the breaker.

Yes, you can use 120v from the same panel to power the relays.

Separate structures like a detached garage require a separate ground rod.

The idea of running a 20a circuit to a 30a relay is fine - most lighting has very high inrush current and will frequently far exceed the rating of a relay. Be very careful in selecting your components. Many relays have a high current rating, but it is for resistive loads like a heating element. Lighting loads are usually capacitive (electronic ballasts, LED drivers) or inductive (magnetic ballasts), and will significantly lower the current rating of most relays. Regarding Fire's comment above about plug-in timers, I have never seen one that will reliably handle the lighting loads like you are considering.

You would be far better off running more relays for future needs and limiting the circuit size to 15 or 20a. If you bump up to 30a, then every component in the circuit will need to be upsized to handle the current - the internal wall wiring, the receptacles, the cordsets feeding the ballasts, etc. These components are large, cumbersome and expensive.

 

[thcrefugee]

You are seriously over complicating it.


All of your lights only equal 10.8 amps @ 240v.
true, for now. and well within 16/20Amps.

You run 1 240v 20 amp circuit to a box, divide that circuit to another box, use 2 plug in timers, thats done.
I want to eliminate the plug in timers all together, which would mean buying 3 new 240v plug in timers.

Now run 1, 15 amp circuit to the veg area, with a plug in timer and thats done.
I can only use two breaker spots. (3 if I really really have to)

You can safely consume 24 amps on a 30 amp breaker.

What I do not see is your plan for misc fans, vacuums, pumps etc.. you should work in a 120v circuit in there somewhere.
that would be handled by the extra 13 useable amps left on the 30amp supply circuit

By over complicating things with relays you are really risking messing something up. If you don't know what you are doing keep it simple the less wiring/wiring connections the better.

I understand how to wire a relay, and I want to control lights on with a simple, low draw trigger wire @ 120V

 

[corky1968]

This is happens when shithawks try to do their own electrical work and they don't have their grade 10.

Trailer Park Boys - Bubbles' Shed Burns Down

 

[thcrefugee]

First, having multiple sources going into a structure can create a scary situation when trying to shut off the power and is prohibited by code except for a handful of exceptions (fire pump power, emergency power, etc). If someone doesn't realize that there are different feeds supplying the area, they can shut off what they think is the power source and there will still be hot circuits in the building, potentially creating a lethal hazard.
This is a very good point, b/c i had only planned on it being a temporary barely buried conduit set-up for a while. But, should something happen while its installed, it would still be a hazard. This is the reason i'm here asking for help.

Yes, you can run 2 (or many more) relays downstream of a single breaker. The 80% rule will apply to the breaker, meaning that any continuous load (any load that runs for 3+ hours) has to stay at or below 80% of the breaker rating. In the case of a 20a breaker, that means that the continuous loads need to be 16a or less, but short-term loads can bump up to the full rating of the breaker.
Perfect, Thats what I thought, but I wanted to be sure
Yes, you can use 120v from the same panel to power the relays.
thanks, thought so, but the stoner brain over thought that one.

Separate structures like a detached garage require a separate ground rod.
Okay, fairly easy to install right?, and even though there is a dedicated grounding conductor from the main? (3 wire with ground..)

The idea of running a 20a circuit to a 30a relay is fine - most lighting has very high inrush current and will frequently far exceed the rating of a relay. Be very careful in selecting your components. Many relays have a high current rating, but it is for resistive loads like a heating element. Lighting loads are usually capacitive (electronic ballasts, LED drivers) or inductive (magnetic ballasts), and will significantly lower the current rating of most relays. Regarding Fire's comment above about plug-in timers, I have never seen one that will reliably handle the lighting loads like you are considering.
Thats what i learned reading. it seems hard to understand all the info for them when it comes to the different load ratings. I was going to oversize here for safety, and future needs.

You would be far better off running more relays for future needs and limiting the circuit size to 15 or 20a. If you bump up to 30a, then every component in the circuit will need to be upsized to handle the current - the internal wall wiring, the receptacles, the cordsets feeding the ballasts, etc. These components are large, cumbersome and expensive.
Is it wrong to think all i needed was the main lug subpanel, main breaker, and wiring? the rest would be routed through 15/20 amp breakers before relays etc. I should be able to stay 20 amp to relays since I wouldnt run more than 3 lights on this same relay.

Thanks for all the help so far.

Now my main questions are, how to run the extra power to the building. If I just upsize the conduit to 3/4 inch, can I run the subpanel wiring through there and maintain "one source of power"?
Already the garage is wired by a tandem 20amp. 2 black, and 2white wires running out there in 1/2 pvc. so is this technically wrong already.
Is it safe to do with clear labeling in the panel box?
It would be 4- #12 wires, and 4- #10 wires in the 3/4 pvc conduit.

The whole reason for building this subpanel/ relay is to keep it safe and done correctly. I need 240V for lights, simple 120v triggers to control them on 2 different light schedules, and 120v for peripherals. the subpanel/ relay boxes seems like the best choice.

Thank you!

 

[FireIn.TheSky]

I understand how to wire a relay, and I want to control lights on with a simple, low draw trigger wire @ 120V

6 of one half dozen of the other. If you are so proficient in wiring relays why are you here asking us to check your work?

Relays are 100% more work and expense compared to plug in timers. Hell even one intermatic hard wire timer is more efficient then the set up in your diagram.

 

[thcrefugee]

This is happens when shithawks try to do their own electrical work and they don't have their grade 10.

Trailer Park Boys - Bubbles' Shed Burns Down

..shithawks, randy.
tpbfukyea

 

[thcrefugee]

6 of one half dozen of the other. If you are so proficient in wiring relays why are you here asking us to check your work?

Relays are 100% more work and expense compared to plug in timers. Hell even one intermatic hard wire timer is more efficient then the set up in your diagram.

im not trying to argue, and apologies if im wrong in sensing a harsh tone.
I figured the standard practice to control a larger set of lights is a "light controller" (Relay Box). I know timers would work, but i really like the idea of a single 120v trigger for the lights running at 240v.

 

[FireIn.TheSky]

Well no worries.

Intermatic makes a 240 timer that you hard wire into, 240v in, set you cycle, it clicks your lights come on, no 120 input needed.

My only thing with the way you want to set it up is you leave a lot more room for failure, failure of components and failure of workmanship.

If I was setting this room up I would 1 20a 240 circuit, slap a timer in line, out of the timer to 2 receptacles, done.

Send 1 240v 15 amp circuit over to the 600w, 1 240v plug in timer and done.

then I would run 1 15amp 120v circuit for convenience receptacles.

 

[thcrefugee]

that sounds like a solid way to go about it. if this room were attached to the house, where the main panel is, then I would do something like that too. However, I still like the finer control that a relay would give.

I also have the problem of limited breaker space, and conduit space and access.
As well as the potential code violation of multiple circuits to the building..?^^ above ^^question.?

 

[FireIn.TheSky]

It is a relay for god sakes, you run a 3 wire romex to a timer, the timer taps 1 leg of the 240 and the neutral to run the timer motor "relay".

It basically allows you to run the relay and the load from 1 wire. The whole point is it saves you from all of the extra wiring runing a separate wire for a physical relay.

What you are proposing will most likely be a code violation, its a mess. You better pull a permit and hire a licensed electrician if you are worried about code violations.

You'll need a trench 18" deep,PVC pipe and wire rated for wet locations, dont be pulling romex underground. THHN is also not rated for wet locations.

 

[rives]

Thanks for all the help so far.

Now my main questions are, how to run the extra power to the building. If I just upsize the conduit to 3/4 inch, can I run the subpanel wiring through there and maintain "one source of power"?
Already the garage is wired by a tandem 20amp. 2 black, and 2white wires running out there in 1/2 pvc. so is this technically wrong already.
Is it safe to do with clear labeling in the panel box?
It would be 4- #12 wires, and 4- #10 wires in the 3/4 pvc conduit.

The whole reason for building this subpanel/ relay is to keep it safe and done correctly. I need 240V for lights, simple 120v triggers to control them on 2 different light schedules, and 120v for peripherals. the subpanel/ relay boxes seems like the best choice.

Thank you!

You are misunderstanding the single power source idea - basically, code requires that you be able to disconnect all power to a structure with a single disconnect (fuse or breaker). What you are suggesting with a larger conduit and adding wires would still give multiple power sources into the building. The best solution would be to set a new panel with a higher capacity feed and pick up the existing circuits out of that panel. You could then either feed your new lighting out of that panel or set a sub-panel that is fed from the new main panel and dedicate that to your lighting.

The Intermatic T-100 series timers are excellent products, and nearly bulletproof. The downside to using motor-driven timers is that the control is coarser but highly repeatable (more of an issue for the grower than the plants), and they cannot be battery-backed so they lose their setting if the power goes off. In an area like I live, the timer would need to be reset quite frequently and can potentially screw up the flowering cycle if ignored. They are also limited to a single circuit, so if you want flowering control and veg control, two timers would be required.

 

[thcrefugee]

You are misunderstanding the single power source idea - basically, code requires that you be able to disconnect all power to a structure with a single disconnect (fuse or breaker). What you are suggesting with a larger conduit and adding wires would still give multiple power sources into the building. The best solution would be to set a new panel with a higher capacity feed and pick up the existing circuits out of that panel. You could then either feed your new lighting out of that panel or set a sub-panel that is fed from the new main panel and dedicate that to your lighting.

The Intermatic T-100 series timers are excellent products, and nearly bulletproof. The downside to using motor-driven timers is that the control is coarser but highly repeatable (more of an issue for the grower than the plants), and they cannot be battery-backed so they lose their setting if the power goes off. In an area like I live, the timer would need to be reset quite frequently and can potentially screw up the flowering cycle if ignored. They are also limited to a single circuit, so if you want flowering control and veg control, two timers would be required.

Thanks again here rives! i very much appreciate the sound advice.

Existing, there is a tandem breaker with two 20 amp circuits run into the garage. so as it sits, it is not up to code. correct?
This isnt my house, and while the landlord knows what I do here, I dont want to make a big fuss out of safely getting more power to the garage.
Obviously, the best thing to do is drop some #8 wire and give them a proper subpanel out there.
However, what can/ should I do to make it the most usable for my situation? (not gonna be here for too much longer- so a "temporary" set-up, and to not alter what is there now..)

 

[rives]

If code compliance isn't a concern, then simply pick the easiest way to accomplish your goal.

If you plan on moving on shortly, I think that I would build the panel and controls up on a piece of plywood that you can easily take with you and demo out the feed when you leave.