I'm looking for an undervoltage trip coil for a Siemens nxplus breaker if anyone can help please?

Have you got a VT signal available? If so, then an undervoltage relay such as made by Woodward SEG, PB Gold, Schneider etc could be applied.

If there's no VT on the customer side, it might be possible to agree to take a separately fused voltage signal from the Metering VT. This will have to be agreed with the DNO, and possibly also your Meter Operator, but provided the overall load burden doesn't exceed that of the VT, it's OK in the UK according to the Metering Codes of Practice (as published by the Balancing & Settlement Code). If you follow this route, be prepared to stand your corner as many DNOs "prefer" not to accommodate this.

Good luck

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Jonno

As Jonathan has suggested, I don't believe they exist. You will need to use the output from a VT (assuming there is one you can use on the circuit / agree use of if it belongs to the DNO). You will then need to use one of the many undervoltage relays, and use this to energise the trip coil on the cirxuit breaker.

Depending on the OCEF relay you are using, you may well find that it has an undervoltage element already fitted, that just needs configuring.

Regards,

Alan.

Thanks Jonathan and Alan.

Siemens do make one - I'm waiting for one to be delivered but it won't be available until mid-October which is rather late for me but now seems unavoidable.

It's to operate with an ABB VSD - due to "fuseless technology", the protection is moved upstream to the primary breaker.