Additional equipment . Total ASC required

[Jeffmo65]

Hi Guys ?
We have been asked to install some additional bits of kit to a small supermarket . Everything is metered ie; lighting , general power refrigeration and so on . We have been told by the consultant that they have an ASC of 60 KVA . I visited site the other day to carry out some investigation . On clamping the singles , I found that
L1 = 128amp
L2 = 92 amp
L3 = 112 amp
Fitted are 200 amp fused main switch .
Now they are also saying they are max ASC Of 57.5 KVA according to their metering analysis .
Doing some 3 phase maths , their statement that they are 2.5 % under agreed ASC doesn't run true as I have them over already . Any thoughts chaps

 

[telectrix]

but how constant are your readings? they could be a peak loading.

 

[Jeffmo65]

but how constant are your readings? they could be a peak loading.

I appreciate your comment . My clamp meter was left on for approximately 2 hrs . Checking at 20 minute intervals , it did not seem to deviate much . There peak reading analysis was
L1= 158.1
L2= 120.2
L3= 154.9
To be honest this just does not equate to me . Perhaps I am doubting myself too much ?

 

[Jeffmo65]

Their running total analysis was
80
53
90
so where do they get the fact they have 2.5% available capacity ?

 

[mechelec]

So they are exceeding their ASC (authorised supply capacity) get in touch with DNO and get an upgrade. This may be as simple as a new connection agreement or involve some major network reinforcement.

 

[Knobhead]

I’ve come across a beauty with this. A company paying for an ASC that the supply couldn’t possibly match. A new substation is now to be installed.

I’ll keep quiet other than the above as this involves another forum member.

 

[Engineer54]

The only way to prove (or otherwise) your concerns is to hire a power analyser and leave it connected to cover at least a week's typical trading days.

Our forum sponsor (test-meter) hires such equipment out. It'll be proof positive one way or the other together with results being downloadable to a computer or printed out in hard copy form!!

 

[Jeffmo65]

To be honest I have obviously seen analysers been used but have never physically connected or used one . So excuse my ignorance in this matter , how complicated are they to read / connect . Apart from being able to interpret the results would I require any additional skills ? .

 

[mechelec]

The ones I use have three rogowski coils for measuring the current and leads for each phase voltage and neutral. You will need the software to download and read the results.
Basic results will be the max, min and average current and voltage. More advanced are harmonic distortion and flicker short and long time.

 

[davesparks]

The basic one I own has three flexible CTs and a 13A plug. It just measures current and the L1 voltage.