Would you extend this RFC?

[Wilko]

Hi - as per Dave.
If the extension has heating that doesn’t rely on this circuit likely the biggest new load will be a vacuum cleaner .

 

[ruston]

I agree too as as long as your ZS is within the the limits of the installation methods .
If I remember correctly 100mtr square was the limit of an RFC without calculation.

 

[Risteard]

The cable length calculation I used was

Vd = L x Ib x (mV/A/M)/ 4 x 1000.
So VD = 113 x 32 x 18 /4000 = 16v

I’ve already divided the end to end value by 4. This is how I was taught to calculate volt drop at the mid point on a RFC.

Does this look correct to you?

I wouldn't use 32A as the design current.

 

[stevethesparks]

if your r1 & rn are 0.84 I would hope to see the r2 at around 1.4

 

[DefyG]

De-rate it to 20A RFC if possible, VD would be less than 5% if using the full 20A load but as the main usage would be the kitchen RFC I doubt the remainder would use 20A (unless electric heating!). Higher max Zs value too!