4-wire plug with no neutral needed or available

[e02325]

I am installing 230 volt - 1 phase equipment in a research lab. The equipment comes from the manufacturer with a cord with a NEMA 14-30P plug (4-wire). However, the neutral is not required, per a note on the equipment drawing that says neutral not connected. The 230 volt distribution in the research lab is 3 phase supplied from a delta secondary transformer, so there is not a neutral available. My question is, can I install NEMA 14-30R receptacles without any connection to the neutral lug on the receptacle without violating the NEC? This receptacle is dedicated to this equipment, i.e. it is not a general purpose receptacle, and could be labeled as "no neutral connected" or something like that. My other option may be to cut the NEMA 14-30P plugs off the equipment and install NEMA 6-30P plugs (3-wire) and NEMA 6-30R receptacles (3-wire). Thanks for your help.

 

[jap]

The connector or receptacle needs to be configured for whatever power source is feeding it.
The arrangement of the Male Plug can accommodate the piece of equipment being served.
Installing a Receptacle or Connector that has a Neutral connection that is not actually connected at the source is poor practice in my opinion.


JAP>

 

[iwire]

Why not just install the receptacle normally with a neutral?

 

[peter d]

Why not just install the receptacle normally with a neutral?

:thumbsup::happyyes:

 

[epimetheus]

OP says lab source is 230V, 3 phase, delta secondary. No neutral available.

Sent from my XT1254 using Tapatalk

 

[qcroanoke]

OP says lab source is 230V, 3 phase, delta secondary. No neutral available.

Sent from my XT1254 using Tapatalk

+1

 

[Rampage_Rick]

Change the plug to 10-30P ?

 

[JFletcher]

Welcome to the forum. Interesting problem. imho, you'd be better off wiring the receptacle correctly (3 wire) and modifying the mfg plug than the other way around, reason being 10 years down the road, you might not remember a 4 wire receptacle lacks a neutral (even tho you have delta service). You may be able to call the mfg and ask if a 3 wire cord is fine.

The mfg is probably assuming that most receptacles are of the type are 4 wire, thus they supplied a 4 wire cord, but dont use the neutral.

Hardwiring may be another option.

 

[GoldDigger]

Just out of curiosity, is your secondary delta corner grounded or ungrounded?

And have you checked with the equipment manufacturer to confirm that it is rated to tolerate 240V to ground on its input terminals?

 

[curt swartz]

Change the plug to 10-30P ?

10-30 = 2 Hots and 1 Neutral. OP needs 2 Hots and 1 EGC = 6-30

 

[Rampage_Rick]

Derp! you're right... That's what I get for not looking at a chart