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#212857 - 02/21/14 01:08 PM L6-30P compatible with 208v three phase power?
EB66 Offline
New Member

Registered: 02/21/14
Posts: 1
Loc: WA
I'm installing a couple PDUs for a high-density server deployment. I'm hoping to use a couple of the 208v circuits that the datacenter has available.

I've been told that the circuits are three phase 208v with a L6-30R receptacle.

However, I can't seem to find any 208v three phase PDU with a L6-30P plug. After further research, I'm led to believe that a L6-30P plug will only work with single phase 208v.

Is it possible for this L6-30P plug to support three phase 208v?

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#212858 - 02/21/14 01:49 PM Re: L6-30P compatible with 208v three phase power? [Re: EB66]
electure Offline


Registered: 12/24/00
Posts: 4226
Loc: Fullerton, CA USA

L15-30 is the correct number for a 208V 3 receptacle.

There is no way an L6-30 receptacle can be configured to work with 3.

The person that gave you the info must be incorrect.

#212859 - 02/21/14 02:42 PM Re: L6-30P compatible with 208v three phase power? [Re: EB66]
gfretwell Offline


Registered: 07/20/04
Posts: 9026
Loc: Estero,Fl,usa
Yup that is single phase only but you do see it hanging on 2 legs of a 3P sometimes.
Greg Fretwell

#212861 - 02/22/14 01:54 AM Re: L6-30P compatible with 208v three phase power? [Re: EB66]
Tesla Offline

Registered: 06/16/04
Posts: 1280
Loc: Sacramento, CA

NEMA L6 connectors are used with circuits with a maximum specified voltage of 250 V. Supply connections are intended for two-pole, three wire hot-hot-ground circuits with a nominal supply voltage of 240 V or 208 V, depending on phase configuration. The L6 connector does not provide a neutral connection.

L6-20 and L6-30 connectors are commonly found on in-rack power distribution units in countries where the mains supply voltage is greater than 120 V. They are also found in the US for heavy-duty 240 V equipment such as welders, where the higher supply voltage allows a lower current draw. These connectors are thus found where industrial equipment or large power tools are commonplace."


[They should've added that these loads are all 1-phase loads. BTW, the 230VAC power tool is typically one that has a LONG extension cord.

When I was a kid, professional Skillsaws were commonly wired for 230VAC. This deterred theft. (Adjusted for inflation, those saws cost $900 in todays dollars! At that price they weren't even personal tools. The boss owned them.) They had r e a l l y long extension cords that reached all the way across the lot! They could tolerate mist and drizzle like no other.]

BTW, I can't imagine that your PDU is actually 3-phase. THAT would be unusual.

So what you've got is a 3-phase panel and just two of the hots have been wired up to each L6-30 twist-lock receptacle.

If you're that determined, it's a pretty good bet that the third phase is passing through those receptacle boxes. A typical wiring scheme would have A&B then B&C and then C&A all in a sequence along a given wall.

In which case, you'd replace the receptacle and tap the missing hot.

But, I don't think anyone is making 3-phase PDUs. Picking up the third phase provides absolutely no utility to the system efficiency (not a rotary load) while constraining the market for a given PDU design.

Edited by Tesla (02/22/14 02:01 AM)


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