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Soowhat 04-06-2012 10:49 PM

MLC-4X Lighting Controller Wiring
I just bought the MLC-4X unit, and information including installation instructions can be found at this location:

This issue has been raised many times on the forum before, but there are always unique situations which make the answers inconclusive. But my situation is pretty straight forward so I hope someone can provide a solid answer.

When I was wiring my basement, I wired my dryer plug with a 2-pole breaker (30AMP). The wall outlet is 4-pronged and can be found here:

This would require 2 hot, 1 neutral & a ground wire. Before the MLC-4X unit arrived, I thought I needed to carry the same wire configuration from the 30Amp outlet to the eventual location of my MLC-4X. I placed 4 runs of #10 conductor in conduit to the area where the controller was to be installed. One side of this home-made extension chord will be hard-wired into the MLC-4X and the other I used the following to plug into the wall receptacle (link provided earlier):

The MLC-4X unit arrived today and the directions only require the user to land a black, red and ground on the unit.

In order to carry the 240V, I need the 2 hot wires, which I assume are the red and black wires as detailed in the MLC-4X instructions. So this means I have the neutral and ground wires left, but only 1 location to left to land conductor.

The following questions I need help with:

1.) Being that I have 4 conductors in my conduit to replicate the wires as they exit the 30AMP breaker in my 200AMP Service Panel, which of the 4 conductors do I abandon within my home-made extension chord?

2.) If the 4th wire doesn't need to be abandoned, would I simply land both the single neutral and single ground on the grounding lug inside the MLC-4X since they eventually meet back at the service panel via bus-bar?

3.) The Leviton 4-pronged receptacle is supposed to receive 4 prongs to run whatever its intended to. If I only need 3 wires to run the MLC-4X, why do 4 prongs receptacles exist?

4.) If a suggested solution is to completely remove one of the 4 wires from my home-made extension chord, I still have a 4-pronged plug engaging my 30Amp wall outlet. Removing one (needs to be identified WHICH ONE) conductor would render one of these prongs useless. Would this be a safety issue?

Please let me know how I am to proceed. Thanks so much!

k_buz 04-06-2012 10:58 PM

are the load coming of this controller 120V or 240V loads?

k_buz 04-06-2012 11:11 PM

Before I go any farther I am going to list two concerns with this product as I don't think it meets code:

1) I don't see a UL seal on it. This product would need to be UL listed to be installed legally.
2) If this controller is used to control 120V lighting, it cannot be fed with a 30A circuit.

Depending on the answer to my question above, I will probably wait till someone else reviews my concerns.

Soowhat 04-07-2012 12:13 AM

MLC-4X - Response
K_buz -

The MLC-4X provides 4 receptacles providing a load of 120V/240V. I plan to plug in my electric ballast, which has 2 modes: 120V or 240V. Please see the link I provided in my post explaining the products specifications. This is a lighting controller fed via a 30Amp breaker.

The 30Amp breaker in my 200Amp Service Panel is

I plan to use the 240V throughout the system. I cannot find the unit is UL listed, but considering the hundreds of positive reviews, if we can just ignore that for now and address the wiring issue. I can call the manufacturer on Monday when they open and ask the question. One reason why it may not have UL listing is because the manufacturer is from Canada and UL is a US standard. But can you PLEASE help me on the wiring issue?


k_buz 04-07-2012 12:43 AM

I'm sorry, I would not install it for a paying customer if it doesn't have a listing agency's seal, so I cannot in good conscious assist the installation for a stranger over the internet.

Not to mention, I have my suspicions of what this is going to be used for which may or may not be legal.

Someone else may help you out, but I am not going to be responsible for burning down your house.

Soowhat 04-07-2012 01:08 AM

You may have your opinion, but in particular states, (Oregon, California, Colorado, Washington among others) it is legal. I don't want you overstepping your moral values, so I respect your decision. Thanks though for your feedback.

a_lost_shadow 04-07-2012 01:45 AM

After looking at the instructions, I don't think it's possible for this device to be listed. Remember that outlets have different blade orientations to prevent someone from plugging a 120V device into a 240V outlet, a 20 Amp device into 15 amp outlet etc. This device has a custom outlet that will accept any combination of 120V/240V and 15A/20A plugs. Since they've bypassed this safety feature, I don't they'll be able to convince a nationally recognized testing laboratory to certify the product. On the other hand, this is just the opinion of a lowly DIYer. So please be safe and consider getting a controller listed.

As a side note, I can pretty much guarantee that if it's not listed, it's not legal in most parts California.

theatretch85 04-07-2012 01:48 AM

Provided your loads are strictly 240 volts only, you would not connect the white wire from your 4-wire plug and connect the green ground to the ground terminal. If it's wired the way the manufacturer intends for it to be wired, there is no way you can safely control a 120 volt load with this controller.

Soowhat 04-07-2012 11:58 AM

Updated Responses:
a_lost_shadow, thank you for your concern. The instructions are very clear that you are to not plug in a 120V device to the controller as its wired from the factory to output 240V. There is language in the instructions saying you can modify the unit to output 120V, but its not recommended. IN regards to controllers and breaker panels, you can always change things around to suit your needs. You just need to know what your doing! :)

theatretch85 - You are correct, the manufacturer (CAP) intends for this device to be used with 240V, which it what I'm doing. IF I understand you correctly, I would land my two hot wires on the "high-power relay lugs" and land my grounding conductor on the grounding lug. The neutral wire would then be abandoned. Abandoning the wire would require me to cap the end as it enters the light controller. However, on the far end of my home-made, 4 conductor extension chord, I bought a 4-prong LEviton Plug which engages the dryer outlet on the wall. What do you suggest I do at this location with the neutral wire heading onto the Leviton 4-pronged plug?

Thanks again for all the help. Really appreciated!

Evstarr 04-07-2012 02:52 PM

Nothing. Just leave it capped at the end.

theatretch85 04-07-2012 02:55 PM

You could connect it to the neutral terminal in your plug and put a wire nut on it at the other end (which is probably what I would do) or you could leave it disconnected in the plug. I've also made plug adapter cables for a welder to plug into a 4 prong outlet in my garage and the plugs I use have the ability to completely remove the prong entirely so with my 220 adapter I just remove the neutral prong and connect to the two hots and ground.

Soowhat 04-07-2012 03:10 PM

Since my last post, I have consulted 2 electricians and they both agreed with Evstarr & theatretch85. The neutral is not needed in this application and it can be abandoned. Being that the unit is 240V, it MUST be served with 2 hot 120V cables. Most 200amp service panels have a common neutral bar where all the whites terminate. This is then tied to the ground as well. So in reality, the neutral and the ground are tied at the beginning. As long as you have a path to ground (either with white or bare copper wire) you have protection. Thanks everyone for your comments. I appreciate all your help.

theatretch85 04-07-2012 03:56 PM

Just DO NOT tie the neutral and ground together at this controller unit!

Soowhat 04-07-2012 09:23 PM

Ha! 10-4. I will cap the neutral inside the controller. I will land the ground on the grounding lug. Thanks again.

gregzoll 04-07-2012 09:28 PM

I just looked at the wiring instructions in the first link, and it is very clear in what is required with this device. Only problem is, they are using the ground in place of the Neutral. I personal would not touch it with a ten foot pole.

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