6KW+ Relay: need help from electrician type

[_Dude]

How to Build a Four Light Grow Light Controller for Less Than $80
http://www.hydroponics.net/learn/grow-light-controller.asp

I want to modify that design to meet my needs:

1. Swap the relay used for a 40 amp relay:

http://www.grainger.com/Grainger/DAYTON-Power-Relay-5Z546
http://www.amazon.com/Dayton-5Z546-Relay-DPST-NO-120VAC/dp/B001GBNYU0

Am I correct that the Dayton 5Z546 will run 6 1000 watt HPS lamps, plus 3 to 6 blowers? The Grainger page says it's 40 amps but the Amazon page says 30. Looking at the Grainger page again, it says the 40 amps "resistive" and 30 amps "inductive," so I'm a bit confused as to whether it can handle 6 1Ks and all the blowers.

2. Swap the 4 stranded cables out for single, solid residential wire running to a row of outlets. I guess I need 6 gauge?

3. Row of outlets: I want to do 6 duplex outlets. Each duplex outlet will run 1 1Kw light, with a plug free to run a blower. I'm not sure how I should connect the outlets to the heavy (6 gauge?) wire. I don't know what kind of box to put the outlets in, either. Do they make boxes big enough to hold all six?

Here's the duplex outlet I have selected:
http://www.amazon.com/20A-250V-Industrial-Grade-Duplex-Receptacle/dp/B005GDFLKA/

4. Swap the dryer plug out with solid residential wire running to a dedicated 40 or 50 amp breaker in a subpanel.

5. Swap the ring connectors out with something that will work with whatever bigger, solid wire I wind up using.

Is all of this doable?

Also, my ballasts are Xtrasuns. Here is the 240V power cord I have selected:

http://www.plantlightinghydroponics.com/hydrofarm-8ft-ballast-power-cord-240v-p-2054.html

Will that work with the outlets I selected?

 

[_Dude]

After looking at some wiring diagrams, I don't think wiring them in line with such heavy gauge wire will be practical. But looking at the design on that page, I don't know if I can fit another 2 ring terminals on each side of the relay either. Could I run short bits of heavy wire to get clear of the relay, then some kind of terminal, and then hook 6 14/3 wires to each with ring terminals? Just trying to think of some way to get a bit more room, in case I can't hook 6 to each the way they have 4 to each in that design.

 

[_Dude]

Maybe a bigger junction box and a couple of bus bars is what I need? Then I can put the bus bars beneath the relay, wire the relay to the bus bars with heavy gauge wire, then run the 14/3 wires from the bus bars to the outlets?

 

[_Dude]

Actually now that I think about it, I should probably just use an Intermatic T-104, lol. They can handle 40 amps.

Anyone got any advice on the simplest way to connect 6 duplex 220v outlets to a T-104?

 

[rives]

The first thing to keep in mind with this is that the circuit protection must be matched to the lightest-rated component in the circuit. So, if you are going to use 15a receptacles, then the circuit needs to be fused down to 15 amps, maximum. If you are going to use 20a receptacles, then the maximum fuse size is 20 amps. If you want to use a heavy feed to the relay(s), then you can put some intermediate fusing between the receptacles and the relays.

As you've seen, there are huge differences in the contact rating of devices depending on their application. Heaters (resistive) are the easiest load to switch. Magnetic ballasts (inductive) are considerably harder on the contacts, and electronic ballasts (capacitive) are even worse.

A T-104 would be a good option if you don't feel like you need split-second accuracy. The motor-driven actuator makes them difficult to set precisely, but they have good repeatability. The best option here would be to get a small sub-panel, say 6-circuit, and feed it with the T-104. You can get protection for each of your downstream circuits and still have the ease of a single heavy feed. You are going to see a hell of a spike in usage when all those lamps come on at the same time, though.

 

[_Dude]

The first thing to keep in mind with this is that the circuit protection must be matched to the lightest-rated component in the circuit. So, if you are going to use 15a receptacles, then the circuit needs to be fused down to 15 amps, maximum. If you are going to use 20a receptacles, then the maximum fuse size is 20 amps. If you want to use a heavy feed to the relay(s), then you can put some intermediate fusing between the receptacles and the relays.

Ah, okay, that makes perfect sense. That's probably why he didn't use outlets in his design, lol. I've decided to just stop being so cheap and buy a controller anyway, but that's good to know anyway so thanks.

As you've seen, there are huge differences in the contact rating of devices depending on their application. Heaters (resistive) are the easiest load to switch. Magnetic ballasts (inductive) are considerably harder on the contacts, and electronic ballasts (capacitive) are even worse.

A T-104 would be a good option if you don't feel like you need split-second accuracy. The motor-driven actuator makes them difficult to set precisely, but they have good repeatability. The best option here would be to get a small sub-panel, say 6-circuit, and feed it with the T-104. You can get protection for each of your downstream circuits and still have the ease of a single heavy feed. You are going to see a hell of a spike in usage when all those lamps come on at the same time, though.

The rest of your info's good, too, thanks for the extensive reply.

Yeah, I'm familiar with the Intermatic mechanical timers and their mushy accuracy, lol. I've been using one to run 3 1ks for years. As you suggest, it's no biggie for a 12-hour timer. They're great until the power goes out.

Got any opinion on the Hydrofarm Autopilot controllers? I'm getting the 8KW 240-only one that plugs into a separate timer. I think for now I'm going to wire it to my subpanel with a 40 amp breaker and a roughly 15' run of 6 gauge wire. 6 gauge is what I need, right?

 

[rives]

Ah, okay, that makes perfect sense. That's probably why he didn't use outlets in his design, lol.

Got any opinion on the Hydrofarm Autopilot controllers? I'm getting the 8KW 240-only one that plugs into a separate timer. I think for now I'm going to wire it to my subpanel with a 40 amp breaker and a roughly 15' run of 6 gauge wire. 6 gauge is what I need, right?

The problem with inadequate downstream fuse protection is present in most cheap lighting controllers, including both the original version of the DIY that you linked and the Hydrofarm unit. The cord caps vs receptacles in the DIY do not make any difference as far as code compliance. If you are looking at a controller that has a high-amperage feed and lower amperage receptacle/cord caps, if there is no intermediate protection to match the lower-rated devices amperage, then they will not meet code.

All of these controllers are in competition with each other, so they are built the same way to stay cost-competitive with each other. Check for UL or CSA approvals - there won't be any. They all rely on a section of the code that allows this arrangement, but only under very tightly controlled circumstances, none of which will ever apply to our situations. The code provision is meant for warehouse lighting, and can only be used if the luminaire hangs immediately below the receptacle; the fixture is connected with a factory-made, specially listed cord no more than 18" long and protected by it's inaccessability; the cord must be visible over it's entire length; any equipment operating under this section of the code can be used for HID lighting only (must power a fixture with a mogul-base, ceramic, screw-shell style lampholder, so no fluorescents, LEDs, or even HID fixtures using lamps like the 315w Philips CDM, etc).

If all of these stipulations aren't met, then the equipment is out of compliance.

[FONT=Arial, Helvetica, sans-serif]Link to code reference

Regarding wire size - with most insulations, #6 is good for 60 amps & #8 is good for 40 amps.
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