3ph US type AC connecor 2

[claver]

Hi,

I would appreciate if someone could enlighten me on US type 3 AC phase connectors and relevant ratings .. here is the problem ..

We have equipment that here in Europe is powered from a 3 ph 32A supply (with Neutral) The electrical connection we make is L1 to N, L2 to N and L3 to N we now have 230V which is powering our 3 battery chargers. Each charger is delivering roughly the same amount of power to the 3 battery banks …so the electrical AC load is relatively balanced … The current for each phase is about 28A. (Hence why we use a 32A 5 pin 3ph socket)

For the US … (this is a temporally installation .. if it was long term another solution might be better, but no time to consider that now unfortunately ..)

I am looking at a “twist lock” type connector.

I propose to go L1 to L2, L2 to L3 and L1 to L3 on a 230V 3 phase supply – I believe in the US that is referred to as a “Line to Line” connection.

Is a 30A 230V 3ph “twist lock” connector rated at 30A per phase ?

What about the power factor ?? Will I require a much larger “twist lock” connector or do I need to do something completely different ??

Appreciate feedback on this

Ian

 

[jraef]

A 30A device can theoretically handle 30A per phase. So technically a 30A receptacle and plug could work, but there is a catch. If you use a 30A receptacle, it must be protected by no larger than a 30A circuit breaker. You can only load a circuit breaker to 80% of its rating, 24A. While it's OK to run a 24A load on a cable and receptacle rated for 30A, you cannot really run a 28A load on it. So that moves you into needing to use at least a 40A circuit, but twist lock plugs and receptacles jump from 30A to 50A. That means you will likely want to use a NEMA L15-50 system.

http://www.stayonline.com/reference-nema-locking.aspx

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[claver]

Thanks Jraef

I find the number of sockets and pin configuration you have in the US bewildering. No issue with going to a 50A system.

If you say we can use 50A per phase ... that would not be 150A in total as I would have to allow for a power factor ?

From a voltage perspective in a commercial building ... 250V, or 480 3ph - are they both equally common ?

The socket you listed is 3 pole - 4 wire grounding. i.e. L1, L2, L3 and ground ?

Have a good weekend !

Ian

 

[dpc]

The 50A plug/receptacle rating is per phase.

250 V is not a service voltage - just the max rating for devices.

Most commercial building will take service at either 480V or 208V/120V three-phase in the US, depending on size, complexity of system, etc.

240V/120V is common single-phase service voltage. 240V three-phase is possible, but almost never in a commercial building.

If you need a three-phase with a neutral, you'll need four insulated pins plus a separate safety ground (green wire). There are various ways of getting the ground connection, depending on the type of connector. Neutral conductor must be white. Phase conductors cannot be white or green.

"The more the universe seems comprehensible, the more it also seems pointless." -- Steven Weinberg

 

[claver]

Thanks for that dpc.

I do not need the Neutral and it looks to me as if it easier to just go "line to line" and get my 208V 3pase that way. Our charger can work from 200V to 240V so 208V is fine

With the 3 chargers each pulling about 30A each.

Each charger connected to its own phase ... then going for a 3 pin + ground 50A twist lock would do the trick.

If what is readely avialable in 3 ph is :

480V - 208V - 120V

and single phase :

240V - 120V

Then I will stick to this voltage range in the future ...

Thanks !