Test Key To Em Lighting Unit Help

[loken31st]

I am currently an electrical engineering apprentice and one of my units is electrical installation, i have a task of wiring an emergency lighting unit from a ceiling rose.

we have been told to use twin and earth from the ceiling rose in the already installed two way lighting circuit to a key test switch and then singles cables from the key switch to the em light, but i have not been told how to wire the key switch and i cant seem to find any diagrams on how to wire them.

i am a massive noob to electrical installation so if you can help please explain it like you are telling a relatively educated child

 

[ipf]

It's only a switch, so have a think.

 

[davesparks]

What exactly do you need to know?
I'm going to give you the benefit of the doubt as you are an apprentice and assume that you don't really need help with the actual connection of a SPST switch, since that is something you learn in primary school!
Presumably you haven't had the actual mode of operation of an emergency light test system explained to you?
In which case it's pretty simple, an emergency light is tested by simulating the condition under which it should enter its emergency mode, but not interfere with the operation of the normal (non-emergency) lighting connected to the circuit.

I strongly recommend that you join the trainee section of the forum, then you will avoid any unhelpful answers on the forum. If you hadn't explained that you are a trainee in your post them my answer to your question would have been a heck of a lot less helpful!


Sent from my iPad using Tapatalk

 

[loken31st]

I'm going to give you the benefit of the doubt as you are an apprentice and assume that you don't really need help with the actual connection of a SPST switch, since that is something you learn in primary school!

i dont know how to wire it up actually, im an electrical engineering apprentice, i work on testing equipment for trains which is very different to normal installations. i dont do a city and guilds course and have no prior knowledge of domestic or industrial installations. my tutor was less than helpful and said something about a chuck block and the wiring was not explained to us before hand. i know how to wire up the ceiling rose and the ELU but dont know how to do the bit in between, do i just choose either the live or the neutral to connect in the actual switch then use a chuck block to join the other conductors?

 

[telectrix]

OK. it's simple really. you need to first find out where the permanent L is for the light. it might be at the light or the switch.then take a feed from the permanent L to the keyswitch, from the other side of the keyswitch, go to the L of the EM. then the N from either the switch or the light fitting (but not switched) to the N of the EM.this way, operating the keyswitch will drop power to the EM without dropping power to the normal light. this would be a non-maintained EM. for maintained there has to be a link in the EM, usually from L to L1.

 

[Deleted member 9648]

A self contained emergency light of the type you are installing consists of a rechargeable battery with a charger,and a relay arrangement. Mains power is constantly applied which keeps the battery charged. If power is lost the relay switches to battery power and illuminates the lamp. The purpose of the key switch is to simulate power loss to the unit to test it is working correctly. Therefore the K/S needs to break the supply to the emergency light.