HQI Lighting

Some advice please.

I have some high intensity lighting above an aquarium, that was wired by an electrician, but I need to check that all is well as it is a very complex job as you will see...

They consist of 3 pendants. Each pendant has 3x400W HQI bulbs and 4x 80w Fluorescent tubes.

Total of 9x400W HQI and 12x80W T5 tubes.

They were wired from a 32A RCBO in a consumer unit with 2 x2.5mm T+E out. This goes to a junction box and a 6mm T+E comes out and goes into a 100AMP switch (used just for on and off). The Live out from the switch is fed into single pole 100amp connection/ distribution block and all the individual lives are taken from this block.

There are six commercial timers that take power with 2.5mm cable from this block. The outputs of the timers (ie on /off ) are fed into 3x25 amp and 2x16 amp contactors. Each contactor has a 2.5mm cable feeding them also from the live block and these then go on to connect to waterproof sockets. Each socket is wired with 2.5mm cable and the maximum each can supply is 2x400W. The control gear plugs into the sockets and onto the pendeants as usual.

The lighting is switched on in sequence with 6 t5 tubes at 11am (from one timer channel), then the second lot of 6 t5 tubes an hour later. These are wired through the 16A contactors).

The Halides then come on in lots of three at 1pm then 1.05pm, then 1.10pm. ( so all 9 on by 1.10pm. They then switch off in a similar pattern with the t5 tubes going out last later at night.

My Q's please.

Is the 32amp Btype RCBO sufficient at the consumer unit?

Is 2x2.5mm cable ok for about a 4m distance in the roof (single storey building runs above the wall and the roof in a channel, with insulation separate from it.)

Is the junction box connecting to 6mm cable ok?.

Is it ok to have the live distribution block giving out all the individual feeds?.... is 2.5mm cable ok to feed the 25amp contactor ( powers up 3x400w each).

Is there a need to wire in another consumer unit with mcb's to supply say the clocks with a 6amp breaker, each contactor with a breaker and so on. If so, what sized breaker and type would you recommend for the 25amp contactor given the load on it ie 3x400W HQI bulbs). I am assuming the startup surge is around 1.6x rated value?....

Would appreciate your advice as initially the live block and the 100 amp switch had 2x2.5 mm cable between them and there was a loose connection that caused a little overheating. This was replaced with 6mm cable and all seems fine, but I want to check that this is the best way to have it all wired up and whether the lighting rig / all it's components should be individually fused/ RCD-MCB'd/ RCBO'd.

I appreciate this is a complex scenario, but would appreciate advice.

I am getting another electrician in to scope it all, but want a number of opinions to make sure it's top notch work and not just overkill for the sake of it.

Are all of the wires of sufficient size for the load?.

Thanks

Moserelli.

3x25 amp and 2x16 amp contactors.

Click to expand...

please expand on this.. 25A and 16A HOW? thermal overloads?

Each socket is wired with 2.5mm cable and the maximum each can supply is 2x400W

Click to expand...

please expand on this also.. 2 x 400W how?


1. roughly 19A FLC from calculated, but more on start up ( so stagering the start is good idea ) and more actual since you get losses from the control gear and extra for the timers etc..

2. bit rough but parallel feeds is ok as long as there's nothing else on one of the legs..

3. I'd prefer 6mm all the way back to the board personally, JB's need to be accessible etc..

4. The block is fine, as for the cable that depends on the answers to the above Q's..

5. I would personally recomend a 40A feed from the other board in 6 or 10mm² 3 core SWA, and a small CU with relavent breakers for the items needed, or possibly a control panel with the breakers and contactors etc all included as needed..



this sounds like a heck of a fish tank by the way..

ColJack said:

3x25 amp and 2x16 amp contactors.

Click to expand...

please expand on this.. 25A and 16A HOW? thermal overloads?

Each socket is wired with 2.5mm cable and the maximum each can supply is 2x400W

Click to expand...

please expand on this also.. 2 x 400W how?


1. roughly 19A FLC from calculated, but more on start up ( so stagering the start is good idea ) and more actual since you get losses from the control gear and extra for the timers etc..

2. bit rough but parallel feeds is ok as long as there's nothing else on one of the legs..

3. I'd prefer 6mm all the way back to the board personally, JB's need to be accessible etc..

4. The block is fine, as for the cable that depends on the answers to the above Q's..

5. I would personally recomend a 40A feed from the other board in 6 or 10mm² 3 core SWA, and a small CU with relavent breakers for the items needed, or possibly a control panel with the breakers and contactors etc all included as needed..



this sounds like a heck of a fish tank by the way..

Click to expand...

Thanks for advice.
I spoke with another electrician who suggested another consumer unit with MCB's as I don't have this protection currently.

Do you know if there are water resistant all in one control panel units that can be used for this job?....I've seen some pictures of one that look like cabinets on the wall if you know what I mean?!. Where can these be sourced.

The only problem is that the original 2.5mmx2 have been plastered into the wall and not sure how best to run another cable?....

Also, the contactors are these

http://uk.rs-online.com/web/search/searchBrowseAction.html?method=getProduct&R=305-1405#header

Each 400w lamp has a separate mains plug (from the ballast), so I can plug two of them into a double wall socket. Each of 3 channels of the timers is powering 3x400W HQI each. 2 of the other timer channels run 6 T5 tubes each (6x80w). The last timer channels runs 2 small fans.


19Amps fully loaded, so the 2.5mm x2 should be sufficient?..(27amp each 2.5mm cable?). They are now hidden as the wall has been plastered and the tank is running.... are 6 or 10mm runs definitely required?.... ie will the 2.5x2 eventually fail?.

Parallel feed refers to the 2x2.5mm cable?. going from the main consumer unit?. These feed only this lighting circuit. Is it acceptable or seen as shoddy work?.

What are JB's?.

Where can I get a control panel..... that sounds like the neatest plan?.....

Thanks for your advice!...

Moser

Here are some pics of when it was wired





The two 2.5mm wires were lengthened by a junction box and 6mm wire run instead.

The distribution block can be seen in the second pic. All the lives are taken from here. The output of the main switch is fed into that.

Everything is hidden in conduit now.

does this seem ok?.

Should I switch over to a dedicated consumer unit with switch, 40 amp? RCD and a load of MCB's for each timer and each contactor?.

given that each contactor is 25amp rated, but running 3x400w hqi lamps., should I put a 20amp mcb on these and say a smaller on on the 16amp contactors for the 6x80w T5 tubes on those?

Thanks for the advice. As you can tell it will be much appreciated to get lots of opinions on this, not just the electrician who will look at it.

Moser

the control panel would be a suitably sized box with a backplate and you make up the controls you want on the backplate and mount it etc..

you could probably just frig what's already there as there seems to be some room in those 2 boxes for a couple of suitable breakers..

JB is sparky shorthand for Junction Box.. you said there is one where it goes from the 2 x 2.5mm² to the 6mm²

As said before you have most of the correct components present, but installed very badly. There is no way i would accept a junction box outsideof the weatherproof enclosure, joing a load of brown single insulated live cables together. Where abouts are you ? I am sure one of us could make a panel up to suit your needs fairly easily . Just need to know exactly whats going in and coming out and what controls what .

Nick

Thanks guys,

I'm in Bristol. I do have somebody coming around for survery of it all.
Do any of you service the Bristol area?.

It would be good to have it all in a custom weather proof enclosure.
The contactors all have spacers in between, so all of the spaces are used up in these enclosures.

I do have one more enclosure that I could have placed next to these.
I could then run the main switch and say 6 RCBO's in the first box to supply each of the timers in the second box and the 5 contactors in the third box.

These then feed the sockets.... since all of the socket are already wired from the contactors, it would avoid duplicating effort, particularly as there is water in the tank and copper wire in the tank could be a disaster for the tank contents!. Also, space to work is a little tight now.

Are the cables used ok for the purpose?.
Is the twin 2.5mm cable suitable to supply this lot?. Apart from running between the roof and the wall, I don't believe there is anything to warm the cable up etc.

I think the enclosures to run quite warm though!.

Thanks
Mo

My God! How big is your electricity bill?!?!?!

I'm looking to have a slightly smaller aquarium myself, maybe two T5s and a HQI. Nothing too fancy. (couldnt afford the running costs!!!)

Indeed, it does all look to be a bit of a mess, and would seem to indicate that the electrician who wired it in probably wasn't au-fait with this kind of work.

Assuming that you have no need to make regular adjustments to any of the timers, it may be easiest for you to purchase (or spec and have custom built) a large GRP/fibreglass weatherproof enclosure fitted out with a backplate and DIN rails, to which you can then mount the necessary contactors, timers, MCBs - and have it all internally pre-wired to a set of input/output terminals that will make wiring in on site a cinch. You should also consider individual MCB protection for each set of lights inside the panel, along with another MCB purely to protect the control side, i.e. contactor coils, timers. You could also fit a main interlocked isolator handle on the front.

If you think you'd need to change the timer settings regularly, then these and perhaps the MCBs could be mounted behind a transparent, weatherproof plastic hinged lid, such that the interior of the controls cabinet wouldn't need to be opened to reset and MCB, etc.

I'm nowhere near you, although taking on the job of building the cab is something that would perhaps interest me, but as it would be a one-off job it would probably be prohibitively expensive - I've got a full time day job, and my time outside of work doesn't come cheap!

Thanks,

If I could have something like this made up, I would be interested.
Then just a weather proof cabinet on the wall that could be wired into from the main consumer unit and I could plug all of the plugs into sockets within it?

If the job isn't hugely expensive, I'd be interested in having it done.

Could anybody quote me something reasonable for a custom built rig?.

You could email me on [email protected]

I need something sorting very soon though....

Thanks

Moser

since you already have most of the bits it would be about £200 + cost of breakers + cost of panel + cost of terminals + cost of time installing it... so somewhere in the region of £400-£450........ ish......