Do these sound right & proper?

a) 2 X 16A immersion heaters in a heatbank

Both on one circuit on a 32A MCB, on a new 2X RCD split CU.
Seperately switched, in two locations viz:-
1) next to heatbank via 2 X switched fused spurs (?) with a 13A (plug
type) fuse in each
2) in neighbouring room via 2 X 45a DP switches (more convenient for
residents to control)

Queries
13A fuses for 16A immersions?
45A DP switches - wouldn’t 20A DP do and be a bit cheaper?


b) Is it a requirement (or worth doing) to cover cables on walls with
plastic capping prior to dot’n’dab plasterboarding and skimming? If
it’s been installed is there any way of checking apart from
destructive investigations?

cheers

JimK

"jim" wrote in message
...
Do these sound right & proper?

a) 2 X 16A immersion heaters in a heatbank

Both on one circuit on a 32A MCB, on a new 2X RCD split CU.
Seperately switched, in two locations viz:-
1) next to heatbank via 2 X switched fused spurs (?) with a 13A (plug
type) fuse in each
2) in neighbouring room via 2 X 45a DP switches (more convenient for
residents to control)

Queries
13A fuses for 16A immersions?
45A DP switches - wouldn’t 20A DP do and be a bit cheaper?


b) Is it a requirement (or worth doing) to cover cables on walls with
plastic capping prior to dot’n’dab plasterboarding and skimming? If
it’s been installed is there any way of checking apart from
destructive investigations?


I would expect two 16A MCBs and two 20A DP switches.

There is no requirement for capping.

Adam

ARWadsworth wrote :
Queries
13A fuses for 16A immersions?
45A DP switches - wouldnt 20A DP do and be a bit cheaper?

The 13amp fuses might well last for months, but none the less they are
not appropriate, nor is the spur unit rated at 16amp.

Two separate circuits from the DB would be a better way to it, each
rated at 16 or 20amp. Failing that, a 2way DB mounted at the far end of
the 32amp feed, with a 20amp rated DP switch for control.

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk

"Harry Bloomfield" wrote in message
k...
ARWadsworth wrote :
Queries
13A fuses for 16A immersions?
45A DP switches - wouldnt 20A DP do and be a bit cheaper?

The 13amp fuses might well last for months, but none the less they are not
appropriate, nor is the spur unit rated at 16amp.

Two separate circuits from the DB would be a better way to it, each rated
at 16 or 20amp. Failing that, a 2way DB mounted at the far end of the
32amp feed, with a 20amp rated DP switch for control.

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk


The OP will have to have a look and see what the "one circuit" that feeds
the heaters consists of. I do like the idea of a 2 way CU at the far end of
the circuit if it is a 4mm or 6mm supply.

Adam

In article
,
jim wrote:
13A fuses for 16A immersions?

Are they actually 16 amp? Common ones are 3kW so 13 amp fusing is fine.
But are normally fed with a 16 amp radial circuit from the CU as that's
the closest MCB - and the circuit will be protected ok by that.

45A DP switches - wouldn’t 20A DP do and be a bit cheaper?

Indeed. Perhaps they had a job lot. ;-)

--
*How about "never"? Is "never" good for you?

Dave Plowman London SW
To e-mail, change noise into sound.