9.5kw electric shower

[Edij]

Hi ,

I'm getting electrician to change my consumer unit and was planning to get :

Wylex WNM1772/1 9 Way High Integrity+Type 2 SPD Flexible Busbar Consumer Unit Loaded with 8 MCB's

Buy online Wylex WNM1772/1 9 Way High Integrity+Type 2 SPD Flexible Busbar Consumer Unit Loaded with 8 MCB's, with 24 hour delivery from Edwardes

www.edwardes.co.uk

it has 2 x 80a 30ma Type A RCD's

but for shower it says -

500 (9.5kW)

41.3

45A

10mm2

RCBO

will this 80a fuse not be like overload or something? Do i need to buy 40-45A fuse?

 

[loz2754]

According to the BEAMA guide that somebody posted the other day, it is. We never fit split load boards but according to this documant diversity IS taken into account when selecting and erecting.

If you have more upto date info can you share please?

Hi. It was me that posted the BEAMA document.
Apparently there is a 2 stage process when applying diversity to a group of circuits protected by an RCD.
Stage 1 work out and apply diversity.
Stage 2 read manufacturers literature.

Excerpt from BEAMA document:

"Conclusion
The minimum rated current Inc of the circuit in the consumer unit for the RCCB
(A) based upon diversity is 78.4 A. However, overload protection shall not solely be
based on the use of diversity factors of the downstream circuits, see Regulation
536.4.202. To achieve overload protection of the RCCB circuit, the rated current of
the OCPD shall be selected according to the manufacturer’s instructions, which for
BEAMA members, is coordinating with the upstream OCPD, in this case a 100 A fuse.
Therefore, the required minimum rated current Inc in the circuit of the consumer unit for the
RCCB (A) is 100 A."


So, overall, not much point in calculating the diversity?