Need some help from wiring sifus

I have a 4 gang switch controlling 4 LED lights (7.5W each) and want to change the switch to single gang, so that i can turn on all the lights at once.

Can anyone tell me if this is possible? and if yes, how would the wiring be like? Is it as simple as connecting all 4 of the light wires into the Load terminal of the switch?

Thanks in advance!

Yes. Make sure it can fit, and not fall halfway out, cause an arc, and a fire that burns down your house.

Thanks. Just want to ask if this is something that is normally done, or something that shouldn't be done? (assuming i take all precautions of course to ensure the fit is good).

Reason why I am thinking of doing this is because I am looking into installing a Broadlink TC2 smart switch. Currently it doesn't work with my 7.5w LED lights due to low wattage (doesn't fully turn off, flickering etc). Would I be correct to think if i connect 4 of the lights into the same gang, it would then be a total wattage of 30W?

It is probably cause by no neutral wire on the smart switch?

Right.. A regular switch will not have a Neutral..

TS needs to pull down a Neutral wire back into the switch box..

Edit* Easiest way to do it is to use one of the existing switch wires as a Neutral and then loop an additional Live wire from nearest light.

This post has been edited by Richard: Nov 29 2016, 07:42 AM

The Broadlink TC2 apparently was designed not to use a neutral line. I.e. one to one replacement with normal malaysian switch. Works with higher wattage bulbs perfectly but just not LED bulbs below 7.5W.

Nice.. Learn something new today.. Haha

looks like you need to modify your wiring a bit?

That is because it uses the circuit as series, sure it maybe ok for large some range of voltage and current. Do you know such switch will create voltage drop, and some sensitive devices will have problem, also for large current operation device may result in burning the switch.

That's a general description for all types of switches..

Conventional pressure contact and thyristor type electronics..

Run the switch at the rated current and voltage only..

Go beyond the specs and you get thermal overload .. You have to know the limits..

Hijack topic a bit. Won't it cause heating?
My switch for heaters have a bit too much wires inside the box. So I lazy cut and just stuff everything in. What I notice is it heats up from time to time. Major problem? It won't heat if switched off right.

Your heater wire carried higher Ampere compare light.

That cause the wire heat up.

Cut short the wire to reduce it. But it still heat up.

Unless you change the wire to bigger gauge.

Thanks dude, not so good at electrical.
So what you mean is, even if I cut it short it'll still be hot. Except now is hotter because I stuff it all inside the box?
Any risk of fire? I can feel the switch is warm to touch, but not hot.

It is not much different because the wire is really not that long. Cut it short is to make it more proper and have some space for the hot air out. (not much also)

You won't get risk of fire if

1) the time using is short.
2) The heater KW doesn't exit the max wire ampere carry. Maybe around 20A. or 4.8kw.
3) the connection not loose and tight secure. switch and heater side.

Get a better higher Amp switch.

I'm using a 20A switch. Probably the wiring then. Find wiring work to be a hassle, especially with switch fittings since it can be hard to get them flush if the box size differ from the switch plate you're using.

Its not the cable length that's the problem..

The higher the current carrying capacity the more the contact area and contact pressure becomes critical..

For round conductors like wires carrying heavy current you MUST use terminal lugs which are properly suited flat and make capacity for the application..

Take a thermal imaging device and point it at the load..

The heat is always at the contact points where the contact area and pressure is the least..

Your item 3 is correct and primary.. Emphasize it more..

I know.

That's why I told him, not much different. But trim down the wire in a tight space will have the wire properly done and some air space. A tight space behind the socket will bend the wire 90degree at the screw contact wire side. With the thick wire usually use in the wall, the wire have intend to brick at the end insulation expose wire side.

You know all this consumer wall socket even a 20A socket don't have a cable lug type of terminal. So you only can tightly screw the wire to get a secure contact.

I usually will strip the insulation longer, bend the wire to equal length and insert into the hole. That increase the wire contact amount in the hole. It also help for the smaller wire gauge that the screw have difficult to lock it.

I use a lot of cable lug in industry. If the consumer socket, plug do have, definitely I will advise them to use it.

ok.. I'm just repeating what's an obvious problem in residential electrical..

The common practice of twisting wires will not work in a heater circuit and will be a fire hazard.. It has to be properly terminated..

It isn't so much a problem with LED lighting but becomes a problem when people are DIY their own heater and aircon terminals..

Be safe..

i tot wires making a small loop carrying high current will act like a heater element?
better not to loop the wire inside the switch box. make a clean connection to reduce the induced current

The actual name is coiling.

Specially extension cord that is wind type. Usually they won't allow over 1000w on this extension cord. Otherwise will heat up in the case.

I usually will pull the whole wire out even in short distance.

Another is the vacuum cleaner. The manual inside will normally advise you to pull the wire out complete and not left some coiling inside.

No.. Its the resistance to electron flow that produces heat ..

Analogy of water through a pipe.. smaller pipe high friction = smaller cable high resistance
bigger cable means higher current flow

Induced current means electron flow picked up from another conductor magnetic field (flux)..

By itself it doesn't produce a temperature rise, nothing you can feel anyway ..

The heat comes from bad contacts, pitting due to electrical arcs..

which is why you must periodically tighten down your connections.. or use a lock washer..

Yes, adding the capacitor could be one option. But I am thinking if I just want to turn on all 4 lights at once, I can just connect all 4 to a single gang model ?

What I am trying to figure out is will the switch now see the total wattage as 7.5W x 4? i.e. Like just using a 30W LED bulb.

The max wattage of the TC2 single gang is about 300W and max 5A, so theoretically more than enough to handle the 4 lights.

Am i looking at this correctly?

yup, technically it's correct.
it should be more than 10W and it should work properly.

try it out and let us know!

Ok thanks. Now i need to figure out how to connect all four light wires safely into the 1 gang switch....

Twitch the 4 wire together and stuck it inside the hole.

Did it work?

it's 2018, hopefully it worked