Anyone heard this one before? Power station

[daveelectrician]

I am currently on quite a big CCTV installation in a new power station.
The original job was to install 2 locally fed DBS fed from 2 new centre tapped 110v transformers to free up ways on the 110v DBS adjacent and supply some of our cameras ( with incorporated heater), the other cameras were to be fed from DBS which are local. The install is now complete and one of the electrical bosses had came to inspect the job,straight away he has said I can't feed the cameras from the DBS as they are centre tapped for the sockets and equipment can't be fed from these transformers. I have had to strip out my other swa's and feed them from my new DBS through a step down transformer.
Does anybody know why equipment can't be fed from centre tapped transformers? Forgot to say that cameras are 24v so need to convert 110v to that voltage at the cameras.
Another question is with my original transformer, I was going to put positive on the brown phase and negative on the black using double pole mcbs, now that I am using a step down do I still terminate my DBS this way or do I terminate it as per usual 3phase DBS with single phasing kit using single pole mcbs?

 

[Knobhead]

Thought this could have been something interesting about power stations.

 

[ian.settle1]

Who specified the job?

 

[SheffSimon]

Which new power station?

 

[daveelectrician]

Which new power station?

Just a new biomass power station nothing huge. The people who have specified the job have now returned to sweden, so now the electrical boss has got involved. They won't let me feed the cameras with 230 v for some reason either.

 

[Knobhead]

What was the original specification?

I’ve had an electrical manager questioning parts of an installation I’d commissioned. The contractor had done everything to the spec and I’d approved it. There was a bit of an altercation with me defending the contractor. “He didn’t like how part of the job had been done”, when I pointed out it would cost the company more to alter it to suit him. He changed his tune.

Check the original specification. If you’ve worked to it, then the onus falls on the new owner. If you haven’t then I’m sorry it’s your problem.

 

[Engineer54]

Tony has hit the nail directly on the head here....

Project specifications rule here, they are part and parcel of the original contract, that would have been signed by all parties. So if you have followed those specifications, any changes the ''electrical boss'' wants to make, will be at their cost!!

That will also be the same for you too, if you haven't followed the specifications, it will be down to you to sort out, and to your cost too!!

 

[Marvo]

Yep, stick to the specs come hell or high water. If someone comes with a 'new spec' then they must issue you with a variation order to cover you and cover the costs.

 

[SheffSimon]

Just a new biomass power station nothing huge. The people who have specified the job have now returned to sweden, so now the electrical boss has got involved. They won't let me feed the cameras with 230 v for some reason either.

May be an ATEX zoning requirement, meaning the cameras are not compliant if fed at 230V?

 

[bcm_spark]

Was you taking the supply from a GIS panel or Non GIS? I suspect you was taking it from the GIS panel which could possibly have an effect on the instruments being supplied by this. As has already being said, refer to the spec, but if you are working where I suspect, the spec is probably scribbled on the back of a smoke packet.