overloading the board?

[JoeDonnelly1]

You know I havent actually noticed the cable size for the supply but its an armour supplying it! And from what i can remember it cant be bigger than 4mm!

 

[Guest55]

If 4mm cable then you certainly haven't got a 63amp supply , 32amp max.
wots the size of the mcb or fuse suppling the extension submains ?

 

[JoeDonnelly1]

Haven't dug that far yet, but as soon as you asked about what was supplying it I was in the regs book... The futher this conversation goes on the more dodgy this is looking!

 

[Knobhead]

What have you actually looked at? I’m sorry but this is the third question you’ve asked today, all about the same job. One oven became two, you feed dribs and drabs of information but your not sure on the information you do give.

This is developing in to pure fantasy.

 

[Farmelectrics]

all the breakers come to 148amps muliply by 0.4 your max demand is 59.2 amps

 

[JoeDonnelly1]

I saw this posted somewhere as another method of working out maximum demand/diversity and this would bring me within the maximum demand if it weren't for biff pointing out the fact the 64A board is supplied with a 4mm cable so it won't actually be 64A, will be going top check out what size of breaker is supplying the board later

 

[Farmelectrics]

ok didnt see that its 4mm supply your right as 4mm on takes 37amp

 

[plugsandsparks]

Diversity calcs are just a guess, the regs give you something to work with but reality will be different. With that type of load you will need to look at the end to end installation from Cu main all the way to appliances. As mention it stuff starts to trip or burn out, i am pretty sure you will be back at your expense and pointing the regs book at the client wont help.
Having said that rating plates are maximums and are rarely encountered and if they are it is for a short duration. This is where experience comes in.

 

[JoeDonnelly1]

Just visited the house, the sub mains board is off a 32A MCB and the CU for whoever asked and is actually ran in a 6mm2 armour

 

[Guest55]

Do yourself a favour pal and walk away.
Find other domestic work to gain experience from as i've a feeling that the customer isnt going to pay to have the job done properly.
The fact that the sparks who put the submains in originally have'nt come back to do the alterations is all the answer i need.

 

[Knobhead]

At long last a sensible suggestion.
The original installer didn’t know what he was doing, neither does our OP.

2 ovens
Induction hob
Ring main
Etc

One 6mm feed, it’s not going to work which ever way you look at it.

 

[nickblake]

Is this a commercial premises or a domestic one? What's the chance they're going to use 2 ovens plus a hob simultaneously? Sometimes a thick coat of common sense can be as good if not better than a diversity calculation.

you,ve never seen me cook then lol