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Posted By: EB66 L6-30P compatible with 208v three phase power? - 02/21/14 09:08 PM
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?

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

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

The person that gave you the info must be incorrect.




Yup that is single phase only but you do see it hanging on 2 legs of a 3P sometimes.
"NEMA L6

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."

Wiki

[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.
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