Don't RCD a kiln. They have high leakage currents. A 100mA split-load
CU is OK, but 30mA and a fused outlet is asking for nuisance
I'd fit a fused spur from a convenient supply, then an unfused
industrial plug and socket (the round blue ones). I'm no expert on
kilns, but I've had plenty of trouble with welders in the past.
Domestic-grade 13A plugtops and sockets just don't like passing 13A
for long periods.
I'm actually in the Republic of Ireland, slightly different wiring
regulations apply however re: the 3KW kiln I would suggest the following:
Treat it like any electric oven. Ideally, if it's in an outbuilding you need
to consult an electrician as the earthing arrangements would need to be
checked over and you could find yourself in SERIOUS trouble if you create a
TT supply in the outbuilding.
As for wiring it up generally:
16A RCD on the board.
Radial circuit to:
20A or 45A Double pole switch and connector unit located near the kiln.
BS1363 should definitely not be used as a connector for sustained 3KW loads.
Blue CEE-17 (Industrial) plugs 16A would work fine. These provide a much
better connection surface on the pins and in the socket than BS1363.
On a modern plug-in kiln the leakage currents shouldn't be large enough to
trip the RCD but it is possible and was definitely a problem with older
Bear in mind it's prob. designed to be plugged in to a European 16A Schuko
(CEE 7/7) socket so should work perfectly well on a 16A radial circuit with
RCD. VDE/Schuko (CEE 7/7) plugs/sockets tend to be far better at handling
sustained 3KW currents without over heating.
Schuko sockets are recessed and thus do not need to have the pins sheathed
(you physically can't touch them while inserting the plug) this allows for a
MUCH greater contact area on the pins meaning they run cooler.
BS1363 plugs and sockets only make contact with the area around the pin tip
due to the sheathing and so as not to expose the user to live metal as
they're inserting the plug
There's also the added problem of the fuse holder.. Which tends to heat up
again due to the very small contact area.. This varies depending on the
manufacturer. Hence you should always use high quality plugs (e.g. MK) on
In general BS1363 plugs are designed for switched 3KW loads, not continious
On 12/01/2004 14:45, in article btubsk$86q$ email@example.com, "R W"
I would suggest the following:
- Put in a proper power feed to a consumer unit in the outbuilding
using SWA cable of appropriate rating. For example, you might want a
total of 32A for everything in the outbuilding. You would protect
the SWA cable and everything downstream with a 32A MCB in the main
house consumer unit or install a separate MCB switch if preferred.
- If the building is some way from the house, the outbuilding should
be treated as a TT system of its own and an earth rod and 100mA time
delay RCD used in that consumer unit. For short distances from the
house you can export the house earth, but it is not a preferred
- In the consumer unit of the outbuilding, put in at least one 6A
breaker for the lights. You don't want them going off if there is an
RCD trip so they/it should be upstream of any RCD.
- For other power in the outbuilding, you should have RCD protection.
Either you can create a split load CU where the breakers between the
main switch and the RCD are not protected and those downstream are; or
you can use individual RCBOs (RCD + MCB together basically).
- For general power, you could create a ring circuit protected at up
to 32A and wired in 2.5mm^2 cable or a radial circuit with daisy
chained sockets in the same size cable protected with a 16A breaker.
- For the kiln, an EN 60309 16A blue industrial connector would be the
best choice. This should be wired specifically to its own RCD
protected or RCBO breaker in the outbuilding CU.
To email, substitute .nospam with .gl
You haven't given enough information, like how the outbuilding is
supplied and if it has a consumer unit or distribution board, and
what sort of earthing your system is.
I would install a dedicated circuit with 16A MCB protection.
I would make the connection to the kiln using an unfused double
pole switch connection unit, wired direct with no plug+socket.
I would not RCD protect a Kiln. The element is likely to leak
anyway which could cause tripping when first switched on after a
period of non-use, but a non-portable appliance of this type does
not present a significant electric shock hazard if the installation's
earthing is correctly installed. However, this means it should not be
connected via a socket outlet in an outbuilding as the socket could
easily be used to power a portable appliance.
The circuit might need RCD protection against a high earth fault
loop impedance. This would require details of your earthing system,
and how the outbuilding is connected to the supply (including cable
type and length) in order to determine if such RCD protection is
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