in this electricians' Q&A video we're going to answer the
question how many lights can i put on one switch now this Q&A relates to the video that Gary and
Gordon made on the Luceco f-type range of fittings and there's a couple of ways that we could look
at it we can look at what's possible but we can also look at what's recommended so we're going
to address this from a domestic point of view and for more information on the rules and guidance
for domestic light installation please check out our free cpd package that we've created on this
subject by clicking the link in the description below now theoretically you need to think about
how much current a typical switch can break most standard light switches can break 10 amps of
current now if we take an f-type fitting they come in a range of power ratings from four to eight
watts so we'll pick one from the middle at six watts do a quick calculation for design current of
power divided by voltage we're going to disregard power factor because i feel our result is going to
be ridiculous six watts divided by 230 volts and we get 26.1 milliamps if we take our 10 amp switch
rating and divide it by 26.1 milliamps we can see that we can operate about 383 light fittings from
one switch now i know what you're thinking is that going to be enough to illuminate my new kitchen it
should be now obviously this is impractical but it does raise the question is there a reasonable
limit on this value well interestingly we find some information in the building regs of
all places more specifically in the domestic building services compliance guide in section 12
of this document which deals with lighting we find table 42 and regarding fixed internal lighting
in the supplementary information column we find this statement a single switch should normally
operate no more than six light fittings with a maximum total load of 100 circuit watts so there
we go the guidance to the building regulations suggests the maximum number of six fittings to
be controlled from a single switch but why is that value of just six fittings recommended if
we could comfortably switch 10 times that amount why is the value of 100 watts mentioned what
percentage of light fittings in a domestic setting need to be energy efficient and just where is
the bar set for a fitting to be deemed efficient or find out the answers to these and other
questions by clicking the link in the description below and taking our free accredited cpd package
on how part l of the building regulations affects our domestic lighting installations but as always
we want to hear from you do you agree with this guidance to the building ranks or do you regularly
operate more than six fittings to a switch well please leave your thoughts and
questions in the comments section below and all that remains in this video is
to say thank you very much for watching
