Inrush currents and solutions......

[Dobes_88]

Good evening!

Wanting to pick the brains of people more experienced in this field, approaching 2nd fix stage of an ongoing rewire where the client wants a shed load of lights throughout.

What particularly worries me is the hallway and kitchen grid switches where there’s around 10-12 lights operated by numerous switches in each area… And he may want a couple more lights added to it!

The plan is to fit fixed Enlite E8 downlights throughout but worried about the dreaded inrush currents, have emailed Enlite to see what sort of figures I should be expecting per unit but no reply as of yet…

Would a better plan to fit LED GU10’s to limit the inrush?

It’s all wired in 1.5mm, clipped direct with switch drops in oval conduit so will be able to get away with a C10 (if Zs in limits), but with the shear volume of lights (around 25-30 x per lighting circuit) I’ve read about these inrush current limiters that could be the solution - but I haven't or know of anyone that has installed them.

Any guidance would be greatly appreciated!

 

[davesparks]

What do your circuit calculations tell you?

How can he calculate this when the manufacturers haven’t supplied the required information?

 

[Octopus]

The guides and regs don't help .... As far as I know they still suggest we should allow 100w per light fitting .....

We all know that this is very out if date...

How many light fittings in total are there on this circuit?

 

[sam400]

I keep telling people installing LEDs is a dark art but no one believes me! Lol
I have fitted quite a few enlites on b curve breakers and not had a problem.
But got caught out once by 3 JCC under unit lights that I had to put on a C10 to stop it tripping.
I recently contacted JCC about some LED panels I was fitting and they said they pull 36A per fitting on start up!
(Only for 20 uS tho)

 

[1Justin]

I'd be surprised if you can get a figure from Enlite, but if you do, then let us know! With domestic lights I don't think you will have a problem though.
I have had issues only once, but that was fitting 11 off 30W floods with Meanwell drivers. I eventually needed to fit a C16 breaker and only just got away with the cable installation I'd already done, phew..

 

[ImpededLoop]

12x E8's shouldn't cause you any issues on a B6 (even on one switch). I've seen it done a few times recently.

If Enlite do supply any data, please share it with us as it would be interesting to look at.

 

[davesparks]

I think one fundamental issue here is that LED lighting is still being installed and controlled by a method designed for incandescent lamps.
Switching and/or dimming the supply to the electronic driver circuitry is never going to give the best results for inrush, lifespan or dimming performance.
Electronics like this performs much better with a constant supply and a separate control input.

New technology needs to have a new approach to the way it is installed and controlled otherwise these problems are never going to go away.

 

[Pete999]

How can he calculate this when the manufacturers haven’t supplied the required information?

Hi Dave I was in a hurry and was going to suggest to the OP that he calculate the circuit parameters to see if he could use a different type of CB

 

[Midwest]

I concur the advice re JCC, so Enlite might be of same assistance.

Although I recently fitted some JCC Hybrid 9's, where there is no such advice on maximum no's on B or C mcb's in the installation instructions. So I rung their technical, who said they don't provide that default info anymore. They did say to ring the local rep, who might provide more detailed information. Looks like their testing has taken some cutbacks.

 

[Octopus]

Initial thoughts is certainly a C6 or C10, will have to see what the Zs is first.

Another interesting strategy ................ if you 1st fixed it you should have a VERY good idea what the Zs is likely to be.................

 

[Dobes_88]

Another interesting strategy ................ if you 1st fixed it you should have a VERY good idea what the Zs is likely to be.................

As in #6 post I've taken over the job from a friend (family bereavement) and client wants some lighting on by end of next week, first time on site yesterday having a nose around and just preparing for worst case scenarios.

Kitchen lighting has around 25 fittings, couple of switches operating 10-12 lights.

Upstairs and downstairs lighting around 35 fittings with hall switch operating around 14 lights.

Upstairs lighting around 35 fittings with landing switches operating around 12 lights, rest of rooms have around 4-8 lights with single switch.

 

[Pete999]

I f as you say did the 1st fix, does he have any proposed Zs calculations from the circuit designs

 

[Dobes_88]

Not that I'm aware of! It's not a massive house so the cable runs aren't too long, will look like Terminal 5 when up and running though!

 

[Octopus]

As in #6 post I've taken over the job from a friend (family bereavement) and client wants some lighting on by end of next week, first time on site yesterday having a nose around and just preparing for worst case scenarios.

Kitchen lighting has around 25 fittings, couple of switches operating 10-12 lights.

Upstairs and downstairs lighting around 35 fittings with hall switch operating around 14 lights.

Upstairs lighting around 35 fittings with landing switches operating around 12 lights, rest of rooms have around 4-8 lights with single switch.

Are ALL these lights on 1 circuit?

 

[Dobes_88]

Are ALL these lights on 1 circuit?

Thankfully not, 3 x separate circuits -

1 - Kitchen lighting
2 - Ground floor lighting
3 - !st floor lighting

 

[Midwest]

As others have said, it would be the switching which might cause the issue. Consider splitting up the luminaires across more switches.