[Question] Compliance certificate and multiple supplies

[christopher john]

To whom may help!

I am trying to find the legislation which prohibits more than one supply under one roof. I have an interesting situation as follows: commercial premises - the main tenant is drawing maxmium load which is a cause for concern regarding the cables and switchgear... there is a commercial tenant under his roof whose supply could be re-routed from his board to the main distribution room which would alleviate his problem somewhat. Any reason why this cannot be done?

Look fwd to your input.

CJ

[christopher john]

Anyone read my question about "one supply under one roof" for compliance issues?

[Sparks]

Not that I am aware of off hand. Check your regs, I don't have time right now. What is an alternative supply other than a 2nd supply?

[christopher john]

Cheers, thats helpful mate...

[bergie]

generally you cant have 2 supplies under 1 roof. its the municipalities,eskom,council that make their own rules. normally if its a separate building on the same erf you can get a separate supply. phone the supplier for that area. you wont find much in the regs

[christopher john]

Tks Bergie, thats just my point. It seems difficult to actually pin point a clause or reg that says what we believe to be the case!
The electricians I have spoken to simply plead a common sense approach as to why they do things sometimes...some things are objective and some of course as a result of "make it up as u go".
Tks for replying. Christopher John

[Dave A]

The big problem you face with multiple supplies is meeting the single accessible main supply isolator requirements.

For example, we're having to clean up a situation with a supermarket in a small mall at the moment. A couple of years back they added a bakery at an adjacent shop, using that supply there for all the baking equipment. That in itself wasn't a problem, but the muck started hitting the fan when they put a doorway through from the bakery into the supermarket.

Then the supermarket needed to add more refrigeration, and the supermarket supply was already being pushed close to the limit.
So they ran a feed to the bank of fridges from the bakery supply.
Then they fed off that line for the revamped deli.

Now when you switch off the main supply for the supermarket, you've still got big chunks in the supermarket live.

Things really went pear shaped when the electrician that has been doing all this applied to the supply authority to upgrade the main supply breaker to "the bakery."
The moment the supply guys saw the doorway between the two shops, the game was up.

We've found similar multiple supply problems in mini factory complexes where two units have been converted into one.
And then a factory site in Jacobs... but describing that mess and how it got to that stage would take more time than I've got available for now.

The municipality guys here talk about the need for a firewall between different supplies. My suggestion is at the very least, think along the lines of the need for a fireman's switch. You need a single accessible mains isolator that will kill all the power in a clearly defined unit that is physically seperated from anything else around it. There shouldn't be any scope for confusion as to whether parts of the installation in the unit are still live from a different supply.

Also bear in mind that a seperate compliance certificate must be issued on each supply. You can't issue a single compliance certificate that covers two supplies.

[christopher john]

Hi Dave,

My situation is almost identical, although controllable and not as extrapolated.
In all of this, I suppose one is trying to find the balance between firstly knowing the law/regs, and secondly, being a good practioner of it! One does not want to be guilty of ignorance (re the knowledge of the law) on one hand, and on the other hand negligent (re not applying the law sensibly which may prejudice the client massively as a result of the electrician not knowing what he is doing).

Many tks for your input. Great help in pulling it together.

christopher john

[Dave A]

Good to hear that helped, Christopher.

Seeing as you're in a similar situation, let me stress that in the supermarket case the mere presence of the doorway had already crossed the line in the eyes of the supply authority. The rest was just a heads up as to what can arise from there...