skronk Posted June 22, 2017 Author Share Posted June 22, 2017 Just spoke to a sparky in Screwfix. (well, claims to be a sparky) Claims you can supply alarm control box mains from light switch !! Surely not ???? Quote Link to comment Share on other sites More sharing options...
sixwheeledbeast Posted June 22, 2017 Share Posted June 22, 2017 You could supply it from whatever you want, that doesn't mean it will conform to standards or safe working practices. Ideally would have it's own MCB in the CU or a spur from a power circuit, but I have seen all sorts in my time. Also it wouldn't matter about the building being complete, most jobs are retrofits. Quote Link to comment Share on other sites More sharing options...
james.wilson Posted June 22, 2017 Share Posted June 22, 2017 a light switch usually has no neutral so id assume either pulling your leg or cretin Quote securitywarehouse Security Supplies from Security Warehouse Trade Members please contact us for your TSI vetted trade discount. Link to comment Share on other sites More sharing options...
norman Posted June 22, 2017 Share Posted June 22, 2017 Lighting circuits are fraught with interference, fluorescents, chokes etc. not good practice. Quote Nothing is foolproof to a sufficiently talented fool. Link to comment Share on other sites More sharing options...
james.wilson Posted June 23, 2017 Share Posted June 23, 2017 most systems are wired 3 plate, id of took his name and get anything to work of a switch Quote securitywarehouse Security Supplies from Security Warehouse Trade Members please contact us for your TSI vetted trade discount. Link to comment Share on other sites More sharing options...
datadiffusion Posted June 23, 2017 Share Posted June 23, 2017 (edited) TBH in the old days, most domestic alarms were in the cupboard under the stairs etc... and that was usually the one place you would find a neutral behind the light switch, as that fitting wouldn't be part of a loop circuit, in my experience anyway. But yes I've been out to a callout where the report was 'alarm sounds whenever cupboard light turned on', this was 3 months in and some moron had wired onto the back of a switch. Of course, back then a 60w lamp would have enough of a resistance to provide a relative neutral to a low load such as a transformer. This was when I worked for a decent setup, but they had used a contractor for the first (and last) time ever on an alarm job. Only the finest... Edited June 23, 2017 by datadiffusion Quote So, I've decided to take my work back underground.... to stop it falling into the wrong hands Link to comment Share on other sites More sharing options...
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