Anyone know about SNE?

[Rockingit]

Got a new supply on a site, DNO delivered it as an SNE (so that's TN-S, yes?), 80A fuse in a 100A labelled head (yes, very clever).

But, I was there when they did it and they only ran a 'single' concentric 16mm in straight from the pole, so I can't see where the N/E separation is at all. Got a Ze of .67 so it's behaving like a TN-S.

But also, as I understand it, the DNO's aren't supposed to provide end dwellings with TN-S straight off the pole?

I'm going to be getting in a bit of a bun fight with them (DNO) over something else soon, so I'd like to be as overall gen'd up as possible!

Cheers.

 

[Knobhead]

Sorry E54 I was being a bit harsh on the DNO’s, I was commenting on the chances of them tidying up the their installation on the pole.

That transformer has me puzzled, the LV is classic for three phase 4 wire. I have seen some transformers where a standard tank is used and blanks fitted to unused bushings.

 

[Rockingit]

Right chaps, back from the brink......was talking to a Western Power design/engineer/planner on the phone earlier who had the lines up on her screen.....seems the guys who attended site either didn't know their arses from elbows (and, you know what? I REALLY hope it wasn't that!!) or just spun me some line because they couldn't be bothered. So: as far as WP are concerned, the overhead HV side is 3 wire 3ph and the LV output is separate L, N, E. Hence why it's been presented as TN-S at the intake.

On another note, it's not looking good for the connection of a ground source heat pump off that line!!

 

[Knobhead]

Shame about the heat pump. It would cost a pretty penny to up rate the supply for it.

 

[Rockingit]

Yes, it's not definite yet, but she advised me 'not to do much more' at the moment!! I'm NOT looking forward to that particular conversation with the client........

I think the concern is more about harmonic disruption back on to the overhead network rather than a loading one. The specified Flicker standard on that particular pump is the worst one, apparently. Don't know much about flicker so will take her word for it!

 

[Rockingit]

And the latest development is.......

WP have just realised that it's only a 15kW transformer. The harmonics they can deal with, even all the other motors and pumps I'd overlooked telling them about isn't going to phase them. But shear numbers of amps will!

The planning engineer and I have finally agreed a figure of 98A as a 'working load' (given that the after-diversity calcs are about 150A).

Cost to upgrade the pole transformer: £4.5k and the client will have to move to whole-current metering which is also likely to smart a bit! Lead time is 6-8 weeks. Client wants to move-in in four.........

 

[Deleted member 26818]

I've still got a call booked for a planner to attend site anyway due to loading issues (AFTER diversity, and even with a pinch of fairy-dust hope and fingers crossed my calcs are running at 140A, almost half of which are on continuous duty - on an 80A head [mis-labelled as 100A]).

I can't see you getting a 100A supply, with a Ze of 0.67Ω.
In fact I'm suprised they allowed 80A, you sure it's not 60A?

 

[Rockingit]

spin - its all irrelevant now, but I know for certain its an 80A 1361 as I took the carrier apart! And no, the DNO don't want to come and arrest me!!!!