add consumer unit

[carrott]

I am looking to add an extra consumer unit to a recent house extension, what cable size is suitable

 

[sparky (sfd)]

why dont you just install a bigger board?

 

[ban-all-sheds]

In no particular order:

10mm
25mm
16mm
1mm
1.5mm
6mm
2.5mm
35mm
4mm

 

[breezer]

carrot as you do not know may i suggest you get a professional in to do it for you.

some jobs are NOT for the diy person, this is one of them

 

[il78]

To do what? (the obvious electrics, but a little more info)

 

[zoltron]

what do you mean get a professional to do it, I replaced mine last week with a larger unit. Okay i'm not an electrician but would say I'm electrically minded, it was dead easy you just need a bit of common sence and a good memory or diagram to remember what circuit goes where. And don't forget to remove the main house fuse but if you are a little worried the local electrical authority may stamp on you for doing this go buy yourself a nice pair of marigolds (only joking)

 

[Lectrician]

Zoltron - I could change the water pump or cam belt in my car.......could a mechanic pick fault.....er.......yes.

We work atleast 40 hours a week with lecky, A diyer can do most things, but I bet all sparks here could pick holes.

Installing a cable to another board requires consideration.

-What is the earthing arrangements?
-What is the anticipated maximum demand?
-How far is the cable run?
-Will the cable need derating due to installation methods?

Once you have answered these, you can select a cable, taking into account the associated volt drop for the run of cable, and ensure it is within the limits for the distribution cable AND final circuits.

You must then ensure than the earth fault loop impedance is of satisfactory value to insure disconnection of the overcurrent protective device protecting the sub-main cable. This impedance must also be low enough to ensure that final circuits can be wired in a conventional method (ie without having to increase the cable sizes on final circuits to lower the impedance).

Once that is done, you must ensure that the earthing conductor is sized adequatly to carry the anticipated fault current.

Running a sub-main needs consideration, and has many variables.

1mm
1.5mm
2.5mm
4mm
6mm
10mm
16mm
25mm
35mm
50mm
70mm
95mm
120mm
150mm
185mm
240mm
300mm
400mm
500mm
630mm

OK, most of these sizes would never be found in a domestic dwelling, but you get the idea.

 

[andy]

120mm


630mm

OK, most of these sizes would never be found in a domestic dwelling, but you get the idea.

630?! was a nightmare puttin a 120mm 4C armoured underground!

 

[Lectrician]

Not sure what the largest 4 core SWA is??? I have used 400mm Single core Aluminium armoureds (copper cores). Thats the largest I have had the privalidge to work with!

 

[plugwash]

high currents are a pita to deal with.

If you really need to move high power surely its better to just use a higher voltage.

 

[zoltron]

The point I was trying to put across is that it is not that difficult to do a simple job like changing a consumer unit to a larger one if none of the variables inside the property have changed. I changed mine because I'm fitting a bigger kitchen later this year, and am moving away from a gas powered kitchen to electric. My intention is to have 2 direct feeds from the CU to the Hob and Oven and 2 ring circuits. One for high power appliances (Washing Machine, Dishwasher, Tumble Drier), and the other for low power appliances (Kettle, Convection Microwave, Fridge/Freezer), my reason for 2 rings is simple, in the past I have had washing machine, dishwasher, & microwave on timer whilst at work, I arrive back home on a few occasions to find nothing has been completed because the power tripped out, this doesn't take much to figure out that the power requirements are too much for the existing circuits as well as highlighting a potential hotspot in the home. I have not jumped to this idea by myself, my brother is an electrician of 11 years and have looked to him for guidance, like he looks to me and my Microsoft Certification when he has a problem with his PC.

Please don't tell me I have no idea of planning cabling routes, placement of objects or knowledge to complete the task in hand. In my job I design plans and flowcharts with complexity like nothing many of you have seen before, and if i'm unsure about anything in the slightest I go to the right person and find the correct information. Why don't you go and try using something like Microsoft Visio fluently and then you'll know what I'm talking about.

 

[floyd666uk]

Wow, so you can use Visio to draw plans?

That doesn't make you a competent electrician mate.

Why don't you go and try using something like Microsoft Visio fluently and then you'll know what I'm talking about.

 

[ban-all-sheds]

A lot can change in 5 years - maybe his competence has vastly increased.

 

[1john]

competence maybe, arrogance deffinatly!

 

[Electrifying]

A lot can change in 5 years - maybe his competence has vastly increased.