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I've been trying to replace a dome camera with a covert camera. the dome camera was red/black - power and white/black to bnc/rg59. On the covert camera there were simply a red and black which i presumed were the power, and a yellow and white wire (no instructions) which i put into a bnc, then to...

cheers, i'll leave it as it is just incase

In an new commercial install, we are planning on using an existing swa fed from the main supply to feed one half of the building. This cable was made in 1988, would you see any issue in using this cable. It gives a insulation resistance of around 300Mohms. I am just wary of the age of the...

An outdoor door socket with inbuilt RCD i installed trips the CU RCD when the test button is pressed on the socket. both are rated at 30ma, but I would of thought that the test button on the socket should not trip the CU RCD, Does this mean its a faulty Socket/RCD? Also if the RCD trips in...

i'm pretty sure it is a pme system as far as I can see. the earth comes off the neutral at the supply. I thought that if the supply neutral is over 150mm, then 50mm equipotential bonding is needed, not 95mm. Is this wrong?

cheers holmslaw, i'll suggest that.

the main building has a steel supported roof, large gurders etc, approx 60m x 20m, these gurders are built into stone walls except in two places were a few steel supports go to the floor. In the adjacent building, there is two walls joined to the main building but none of the metal structure...

If you have for example a supply cable neutral of 185mm, then the bonding to the steel works etc, needs to be in 50mm earth. However, if this supply feeds another board in an adjacent room which has a seperate steel structure, but is part of the same building, would the bonding to that need to...

I was told not to worry about it, but thought i'd better ask the question, cheers

I'm working on a job, where the 3phase supply is 185mm cables going to the main switch. However, the supply coming in via the main fuses looks much smaller. Which cable size do we take into account, the unknown incomer size, or the 185mm into the main switch? Cheers

I simple question i'm sure but I thought i'd better check just incase. On for example a 63a triplepoled mcb, does each pole have a rating of 63A or idoes the mcb as a whole have a rating of 63A.

the heater is on the same phase as the cctv and as far a i can see doesnt go within a few foot of any cctv coax. the security room is about 3m away from the db, and only one monitor goes funny and 3 or 4 cameras on one multiplexer. Could it be intereferance on the supply or is it probably a coax...

I've recently installed a curtain heater in a shop fit, however when it is turned on the cctv at the complex goes fuzzy. Its wired into the same board that the cctv is but in a different mcb. How can i get rid of the interferance without rewiring the heater somewhere else? cheers

Hi, Are there any fire sirens that are suitable for outdoor use?

A few questions on emergency lighting, Is it ok to wire it in standard t/e, as I have seen some in a white fire type stuff and some in normal t/e. I would have thought it would need to be wired in fire retardent stuff??? Also would you wire the emergency lighting into its own MCB or would...

I've just had the debate with a collegue with him saying neon screwdrivers are not reliable up ladders coz theres no earth path or something. I said that when using a neon screwdriver, I act as the earth for it, so doesn't matter if I jump up in the air the neon will still light up. Who's...

I'm doing some SWA glands into metal and plastic boxes. The metal ones are easy(ish). But when i'm trying to fit the gland into a plastic box it sometimes cracks the box (cheap crap plastic socket box). Is there a better way of doing these glands? or a different way to put a swa into a...

I've changed a few faulty sounders on a fire alarm, however, there are at least two sounder circuits, with both mains powered and low voltage ones. Is this very common? I changed 5 sounders and put low voltage ones in, however I didnt notice one was mains powered as when we tested the panels...

cheers guys

Can standard T8 fluorensent tubes be used in a high frequency fitting or do they need to be high freq tubes?