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the Big Cooker repair company |
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How can the cooker be
connected to a 45 amp supply when the rating plate states the cooker draws 70
amps? An electrical rule
called Diversity. The IEE Regulations 15th Edition gives a simple method of
diversity calculation for household electric cooking appliances. Take the full load of the cooker,
then deduct the first 10 amps. Take 30% of the remainder and add the
first 10 amps originally deducted. If an electrical socket outlet is
incorporated into the cooker switchbox, add 5 amps to the total load. A worked example would be:- Cooker rating plate full load 70 amps. Taking away first 10 amps would leave 60 amps. 30% of 60 amps is 18 amps. Add the 18 amps to the original 10amps deducted
(15amps if there is a socket) Answer is 28 amps (33amps if there is a socket in
the switch unit). Requesting a 45 amp
supply gives a good safety margin. The reasoning behind
the calculation is that not all heating elements are constantly on together.
Element thermostats and energy regulators cut-in and out in use, spreading
the electrical load. There is also a
European method from Cenelec for calculating diversity; this uses equations
and the number of heating surfaces in an appliance. Although this usually
gives a slightly higher diversity current it is always on a par with the
simpler method. Will the engineer need to
switch-off the electrical supply? The installer must be able to switch-off the electrical supply when
installing your cooker. If he is unable to isolate the supply at the
connection point, he will not to proceed with the installation on a point of
safety. Does the cooker need to have its own
switch? In an ideal installation scenario, an accessible double pole switch
(switches both the live and the neutral) should be installed within 2 metres
of the cooker, this being hard wired directly to a cooker connection point
behind the appliance. The switch should not be directly above the hob area
but should be within 2 metres of the cooker. To ensure safe isolation during
future cleaning and servicing, all switches should be easily accessible and
of a double pole type with at least 3mm contact gap. What tests will the installer carry
out during installation? During installation, the installer will undertake safety
earth-continuity tests and earth resistance tests to ensure the cooker is
safe for use. He should also make a visual inspection of the supply wiring
and fuse/circuit breaker to ensure it is adequately rated. |
Electrical FAQ’s
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Tel:
01772 46-56-76 Fax: 01772 46-47-57 Email: enquiry@BigCookerRepair.co.uk |
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