On 01/06/2021 13:49, Grumps wrote:
On 01/06/2021 09:32, Grumps wrote:
On 29/05/2021 13:21, John Rumm wrote:
On 28/05/2021 17:22, Grumps wrote:
Hi,
I've just had an EICR performed on a property that I let. I wasn't
present during the test and my tenant has reported the following
back to me (I'm too impatient to wait for the full report which
might not be with me until the end of next week).

Apparently 4 16Amp MCBs need to be changed to 6Amp. Each MCB is
connected to just one wall-mounted electric heater. The heaters are
rated from 1500W to 2000W.
The last time I had a look at the wiring (when I decorated some 4
years ago), I'm sure it was 2.5mm2 from the MCB to each heater's FCU.
2.5mm2 and 16A MCBs are a good combination, yes? Even 1.5mm2 should
be good.

Surely if I get the 16A breakers swapped to 6A then that won't be
sufficient for a 2kW heater, and probably not even for the 1500W ones?

What possible reason would the electrician suggest swapping to 6A MCBs?

It seems like you will need to wait for the proper report since
something does not add up here.

I have the full report now.

All circuits have been deemed to be reference method 100.
The 5 heaters are on 1.5mm2 cable with 16A MCB.

The failures are listed as:
3x 1.5mm cable in a 6A breaker (these are lights and smoke detectors).
Incorrect breaker sizes for heater circuits.

Recommended solution:
Downgrade MCBs to 10A C type for inrush protection of 1.5mm cables.
Split the doubled up 6A circuit.

So my quick questions a
Are you not allowed to have 3 circuits in one breaker?
Can you not protect 1.5mm2 ref method 100 wiring with a 16A breaker?

The electrician quote to "mend" this is £205 inc VAT.
Ta.

And finally, from the electrician...

6242Y PVC/PVC COPPER CABLE is rated at approx 13amps it is therefore
good practice to downrate the mcbs from 16a to 10a to protect the cable

By replacing the mcbs from B type to C type this will reduce the risk of
nuisance tripping when the heaters click on and off at full load



Your electrician meant (assumption) to say 1.5mm 6242Y cables is rated
at 13A using installation method 101. The CCC of 1.5mm using method 100
is 16A.

I can see why he has flagged it but there is nothing unsafe as long as
the end load only consists of a 13 fused spur. So yes it is good
practice to downrate the MCB if there is a chance someone uneducated
might alter the circuit.

It's probably better to get the MCBs swapped than have C3's or comments
on your EICR.

Note that the OSG does not give a guide for a 1.5mm 16A 101 installation
method radial circuit as it assumes a terminal load of 16A.





--
Adam