Wiring L14 Receptacles

[DataCenterGuy]

Is it legal to wire an L14 Receptacle to 2 Phases + Neutral of a 3-Phase Circuit? I've always understood an L14 to be for 3-Phase + Ground, and L21 to be used when both 120V and 208V services are required.

The only thing I can find in the Code is 406.3 (F) which I read as precluding this usage if L14's are also used elsewhere on the premises for 3-Phase (No Neutral) service.

If 2-Phase + Neutral connection to an L14 is permitted, would it need to be identified?

 

[infinity]

My default answer would be to check the listing of the device but there might be some other prohibition.

 

[iwire]

I would cite 110.3(B).

It sounds like a good way to single phase a three phase machine equipped with an L-14P

 

[curt swartz]

L14 = 125/250 L1, L2, N, G
Your first description would be the proper way to connect it. It is not a 3 phase configuration.

 

[Little Bill]

L14 = 125/250 L1, L2, N, G
Your first description would be the proper way to connect it. It is not a 3 phase configuration.

I agree. The OP may have seen the NEMA description of 3-P 4-W. The P is for pole not phase.

 

[DataCenterGuy]

Thanks! Case Closed !

Thanks! Case Closed !

I agree. The OP may have seen the NEMA description of 3-P 4-W. The P is for pole not phase.

Thanks for pointing out the obvious that I should have seen myself. Amazing you can get stuck in a through :ashamed1:rut and overlook what's staring you in the face!

 

[Little Bill]

Thanks for pointing out the obvious that I should have seen myself. Amazing you can get stuck in a through :ashamed1:rut and overlook what's staring you in the face!

You're welcome!

 

[davidaengelhart]

3-phase + ground is L15 for 208V, L-16 for 480V, and L17 for 600V.
The L-14 should have a silver screw for the neutral per 200.9 AND 200.10.

 

[swei]

Is it legal to wire an L14 Receptacle to 2 Phases + Neutral of a 3-Phase Circuit?

This is relatively common in datacom and temporary power setups. Most of these actually run two sets of 120V loads, but a few actually utilize both voltages.

There is some truly ancient 240V equipment will balk at 208V (not our problem) and of course the 25% hit that resistance heating suffers.

I would cite 110.3(B).
It sounds like a good way to single phase a three phase machine equipped with an L-14P

If someone wires a three-phase machine to an L-14P, they deserve what they get. The same idiot could just as easily wire something to a 347/600 plug.

I prefer to use L21 receptacles and then manage phase balance by wiring the cords differently, but there is nothing inherently unsafe about using an L14 device in this configuration.