Sub main to house

[davesparks]

i think you should stop before you hurt someone, a little knowledge is dangerous

for a start 13a? thats an odd size

what happens if they want a shower?

an 8kw shower is around 30odd amps, electric hobs etc are usually fed from 50amp mcb's

60amp supply is pushing it a little

60A supply isn't pushing it for a house at all.

And 50A for a domestic hob is bit overkill don't you think?

 

[shanky887614]

60A supply isn't pushing it for a house at all.

And 50A for a domestic hob is bit overkill don't you think?

what im saying is a lot of people are going for electric showers, induction hobs etc now so they are using a lot more electricity than they used to


at Christmas with hob, oven and electric show going plus heating could trip iit

 

[HandySparks]

The most pressingissue for me is to get the right SWA ducted and installed in the trench whichhas already been dug. It's collapsing in this weather and is alsocompletely obstructing access to the site!

In which case, providing it's deep enough, lay a suitable size of duct in with appropriate backfill and warning tape. Take photos and measurements to show your electrician. Then he can come along later and pull in whatever cable is required.

 

[jonA]

First, my apologies - I copied and pasted my last from Word and it all came out wrong. Makes it difficult to follow so I will try posting it again.

Meantime, for 13A RCBO, please read 16A!

Also, the 'house' is more an upmarket shed and will have minimal power demand. There won't be an electric shower or hob, just a few power and lighting circuits. 63A will be more than enough!

 

[davesparks]

what im saying is a lot of people are going for electric showers, induction hobs etc now so they are using a lot more electricity than they used to


at Christmas with hob, oven and electric show going plus heating could trip iit

Why do people always harp on about christmas dinner when discussing cookers?

Diversity applies on the 25th of December exactly the same as it does every other day of the year!

 

[shanky887614]

Why do people always harp on about christmas dinner when discussing cookers?

Diversity applies on the 25th of December exactly the same as it does every other day of the year!

on christmas your more likely to have meat slow cooking in the oven and things on the hob while people are in the shower and playing games so demand is higher for a lot of people than any other time of the year

 

[telectrix]

on christmas your more likely to have meat slow cooking in the oven and things on the hob while people are in the shower and playing games so demand is higher for a lot of people than any other time of the year

good point. i have a shower at xmas, whether i need one or not. it's a bugger xmas day as the takeaway is closed and the cooker has to be turned on.

 

[davesparks]

on christmas your more likely to have meat slow cooking in the oven and things on the hob while people are in the shower and playing games so demand is higher for a lot of people than any other time of the year

Diversity will be the same as any other day of the year though.
The oven and hob elements will go through exactly the same cycles as they always do.

 

[ImpededLoop]

good point. i have a shower at xmas, whether i need one or not. it's a bugger xmas day as the takeaway is closed and the cooker has to be turned on.

That's where you're going wrong. Save the shower until Boxing Day when you're eating cold leftovers. That's how diversity should work!

 

[Octopus]

Guys,

I think some difficulty has crept in becausethe power supply is arranged back to front to the customary set up.

There has been a lot of debate here aboutexporting a supply from a house to an outbuilding and there doesn’t seem to bea consensus on this – specifically whether the earth in a PME installation canbe exported, and, if so, how.

In my case, the main fuse and meter arelocated in a garage. I have been using trailing leads from here to carry out buildingwork. The connection in the garage is currently a TT though the DNO is scheduledto convert it to PME shortly.

Building work is now pretty much completeand I want to connect up the house which is about 30m away.

There appear to be two alternatives:

1. Install sub main
   
   Garage consumer unit
   100A RCD 100mA timedelayed
   63A MCB for sub main tohouse
   13A RCBO for local powercircuit
   
   Sub-main to be 3 core16mm2 SWA with third core and armour bonded to MET at each end. As I understandit, the house and garage will then be in the same equipotential zone so acommon earth path is okay.
   
   House consumer unit
   100A DP isolating switch
   3 x 6A RCBO 30mA forlighting circuits
   3 x 13A RCBO 30mA forpower circuits
2. Split meter tails via Henleyblock to:

1. Garage consumer unit

100A DP isolating switch
13A RCBO 30mA for local power

1. Garage isolator switch

100A RCD 100mA time delayed

SWA cable and bonding to be the same as if sub main were installed.

House consumer unit
100A DP isolating switch
3 x 6A RCBO 30mA forlighting circuits
3 x 13A RCBO 30mA for powercircuits

I’d very muchappreciate your advice as to which of these arrangements you think would work best inpractice.


The most pressingissue for me is to get the right SWA ducted and installed in the trench whichhas already been dug. It's collapsing in this weather and is alsocompletely obstructing access to the site!


Last query, if Imay: I would like to use metal clad consumer units for the installation for bothaesthetic and robustness reasons. Recognising that they would have to beearthed, is there any reason why I shouldn’t specify them?


As ever, helpfuladvice would be much appreciated.

Cheers, Jonathan

Sensible advice:

1. Post your location

2. Get 3 or 4 LOCAL compentent sparks to quote

3. Select best option (not always the cheapest)

4. Get work done


Simples.