Number of Lights on Domestic Circuit

[Malcolm-Ipswich]

My house has 2 lighting circuits each protected by a 6 amp trip. I have read that it is normal to have upto 12 lights on each circuit which allows for upto 100W bulbs per lamp and 1200W max loading. I would like to ask whether there is a mandatory maximum number of lamps or is it advisory/best practice. I have done a quick count up of my upstairs circuit and already exceed the number of lights but not the circuit rating with the current lights in use e.g. I have some low energy bulbs and a study has florescent tubes. I also wish to add an ensuite bathroom which will have 3 * 50W lights,a shaver point and extractor fan and a couple of 60W wall lights in the main bedroom. This would still fall within the circuit rating but significantly exceed 12 lights. Would an extra lighting circuit be required? Any advice would be welcome

 

[dingbat]

Malcolm, 230V x 6A = 1380 W.
12 x 100W lamps is a rule of thumb guide to the number of utilisation points per 6A circuit, but (as long as you're not overloading) you can have as many lamps as you want.

 

[The Jeep]

That's right. Also consider that you're unlikely to have all lights blazing simultaneously. If you were to overload the circuit(s) with too many lights all on at once, the protection device would (should!) trip to protect the cable from melting. Best to stay below 1380W total load per circuit, though. You can get devices for measuring the current being drawn on each circuit at the consumer unit, or you can add up the actual power rating of each lamp.

 

[plugwash]

i'd count fittings that can take a standard bulb as if they had the appropriate standard bulb fitted (since they are likely to get changed to one in the future).

I also think that leaving all lights on upstairs is not at all unlikely, if every bedroom is occupied they will all be lit at certain times of day, the passageways will probablly also be lit and i don't think people tend to turn off thier bedroom lights when going to the bathroom.