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?

 

[LewisM]

You need a lot more than a consumer unit to fit a consumer unit.

 

[brianmoooore]

An RCD is not a 'fuse'. 80A is its maximum load, and the sum of the MCBs running from it must not add up to more than 80A, unless your DNO fuse is 80A or less.
Following on from another thread I've just posted on, is the shower rated at 9.5kW @ 240V or 230V?

 

[Edij]

An RCD is not a 'fuse'. 80A is its maximum load, and the sum of the MCBs running from it must not add up to more than 80A, unless your DNO fuse is 80A or less.
Following on from another thread I've just posted on, is the shower rated at 9.5kW @ 240V or 230V?

Shower info - A Power Input of 240 V and 40 amp circuit breaker is required for max output ( 9.5 KW )

in simple words ,if i buy that consumer unit ,will i need to buy any extra wylex fuses or what is there included is good enough?

 

[brianmoooore]

The standard UK voltage is 230V, not 240V, so your shower is rated at 8.275kW in reality. The 9.5kW is marketing.
The current drawn by this will be around 36A, so yes, you do need to buy a 40A breaker AND, the sum of the breakers on the side of the CU you fit this must not add up to more than 80A, unless you can confirm that your DNO fuse is not more than 80A.

 

[Edij]

The standard UK voltage is 230V, not 240V, so your shower is rated at 8.275kW in reality. The 9.5kW is marketing.
The current drawn by this will be around 36A, so yes, you do need to buy a 40A breaker AND, the sum of the breakers on the side of the CU you fit this must not add up to more than 80A, unless you can confirm that your DNO fuse is not more than 80A.

ok got it! so something like this?will this be compatible with that consumer unit?

Wylex MCB

6kA

www.toolstation.com

 

[littlespark]

Can you ask you electrician to supply the board, with the size of this shower in mind?

Some dual boards like this come with RCBO’s instead of RCDs

 

[brianmoooore]

ok got it! so something like this?will this be compatible with that consumer unit?

Wylex MCB

6kA

www.toolstation.com

That should do, if you insist on sticking with a dual RCD board.

 

[Strima]

Why is your electrician not specifying what board and protective devices you need?

 

[Wilko]

Why is your electrician not specifying what board and protective devices you need?

No mysteries left in my life ...

 

[Montybaber]

An RCD is not a 'fuse'. 80A is its maximum load, and the sum of the MCBs running from it must not add up to more than 80A, unless your DNO fuse is 80A or less.
Following on from another thread I've just posted on, is the shower rated at 9.5kW @ 240V or 230V?

Is diversity not taken into account?

 

[brianmoooore]

Not any more.

 

[loz2754]

Is diversity not taken into account?

Diversity alone cannot be used, only in consultation with the manufacturer's instructions/specifications.

 

[richy3333]

Not any more.

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?

 

[brianmoooore]

I'm now retired from active contracting, so do not posses a copy of the 18th, although I try to keep up to date with changes from the 17th.
My information comes from recent previous posts on here, and as I understand it, it's a recent change.

 

[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?