Dimmer Racks in Schools

[iamchristuffin]

Hi.

 

My school is nearly finished building a new drama studio, in which are going to be installed 2x 24 ch Chilli Dimmers running off 120A. I asked a friend why they were installing Chilis instead of sockets to connect Betapacks or whatever to, and he said that the use of pluggable dimmer racks in schools was considered bad practice now, because of all the power that could fry little children. (This bit I know)

 

Is this true about Chillis Vs sockets, or is it just one man's opinion??

 

Thanks

[dave singleton]

One mans opinion I would say. I will point out I don't no of anything of this nature being stated recently and I am pritty sure I would catch on if it was considering alot of the installations the company I work for does is for schools.

[Andrew C]

When I specified 63A sockets in our theatre (before the days of formal RAs) I had interlocked switched sockets fitted. Stupid kids could stick fingers, screwdrivers etc into the holes otherwise.

 

In hindsight, I'm not sure I did the right thing; see my sig for reasoning!

[Trunker]

In a school I would recommend a 'hard wired dimmer'. It is mainly because of the power going through the dimmers but here are another 4 reasons why.

 

They are cheaper to build

they take up less space than the 'patchable dimmers'.

Less high power Sockets are requireds

Schools are not supposed to have 3 phase (415) running on lighting systems. By putting in hard wired dimmers they can some how spread the load over the dimmers to make it legal. (thats what one of the technicians form stage electrics told me anyhow)

 

What board are you having? You should be able to 'soft' patch off the board anyhow.

[iamchristuffin]

In a school I would recommend a 'hard wired dimmer'. It is mainly because of the power going through the dimmers but here are another 4 reasons why.

 

They are cheaper to build

they take up less space than the 'patchable dimmers'.

Less high power Sockets are requireds

Schools are not supposed to have 3 phase (415) running on lighting systems. By putting in hard wired dimmers they can some how spread the load over the dimmers to make it legal. (thats what one of the technicians form stage electrics told me anyhow)

 

What board are you having? You should be able to 'soft' patch off the board anyhow.

 

 

What do you mean by build? Chillis are cheaper for the system we are having, but only by about £300

We have a 63A 3ph in our main Theatre, but all the performance are 'owned' by a company (The company's director is the bursar at school- I think), which allows them to be rented out, so I think that makes it OK for 3ph to be installed (?)

I wouldn't agree with the less space, personally. I saw 3 of the Chilli spec we are having at the little Theatre in Wells, and they took up an entire wall, whereas the dimmer racks at school at the moment take up about half of the wall space, although they do protrude a bit.

I believe it's another FatFrog, which makes sense, as we already have one in our Theatre, although I wanted something more...exciting (!)

Thanks

[3guk]

Schools are not supposed to have 3 phase (415) running on lighting systems. By putting in hard wired dimmers they can some how spread the load over the dimmers to make it legal.

 

Since when and how ?? I'm a tad confused at that comment tbh.

[iamchristuffin]

Schools are not supposed to have 3 phase (415) running on lighting systems. By putting in hard wired dimmers they can some how spread the load over the dimmers to make it legal.

 

Since when and how ?? I'm a tad confused at that comment tbh.

 

 

That's what I thought, but I'm sure Trunker has been doing this for a hell of a lot longer than I have, and is therefore probably more knowledgeable, so I decided to leave it. Now that someone else has questioned it.....

[Ynot]

In a school I would recommend a 'hard wired dimmer'. It is mainly because of the power going through the dimmers but here are another 4 reasons why.

 

They are cheaper to build

they take up less space than the 'patchable dimmers'.

Less high power Sockets are requireds

Schools are not supposed to have 3 phase (415) running on lighting systems. By putting in hard wired dimmers they can some how spread the load over the dimmers to make it legal. (thats what one of the technicians form stage electrics told me anyhow)

Sorry to be blunt here, but....

RUBBISH!!!!

Whilst they may indeed be cheaper to build, hard-wired systems can cost more to install. (Not always though)

 

Many schools have Betapacks and the like hard-wired and wall-mounted - they DON'T have to be fed by a 63A wall socket. (Of course, if they are that gives more flexibility, but that's another argument).

 

There is NOTHING to say that schools, or anywhere else, cannot use 3-ph power at all!

There USED to be an OLD reg that has long since been rescinded that restricted close proximity of separate phased outlets, but that died ages ago, and was nothing to do with scools, anyway.

 

And finally, hard-wiring dimmers cannot possibly spread the loads, because HOW can anyone dictate what lanterns will go on which sockets at the other ends....??

And load-spreading would be more logical to attempt on 3-ph setups anyway...!

[Trunker]

I was at school when Stage electrics done an install for a school in south wales. These are more or less the reasons they gave. Only going by what the 'pros' told me.

 

In a school I would recommend a 'hard wired dimmer'. It is mainly because of the power going through the dimmers but here are another 4 reasons why.

 

They are cheaper to build

they take up less space than the 'patchable dimmers'.

Less high power Sockets are requireds

Schools are not supposed to have 3 phase (415) running on lighting systems. By putting in hard wired dimmers they can some how spread the load over the dimmers to make it legal. (thats what one of the technicians form stage electrics told me anyhow)

 

What board are you having? You should be able to 'soft' patch off the board anyhow.

 

I believe it's another FatFrog, which makes sense, as we already have one in our Theatre, although I wanted something more...exciting (!)

Thanks

 

If you want something more exciting ask for the Strand Light Pallette Classic. More than you will ever need. (this side of 2015 anyhow). Or if you want to stick with Zero88 get a mambo or leap frog. Same board but can control more intelligents.

[Ynot]

I was at school when Stage electrics done an install for a school in south wales. These are more or less the reasons they gave. Only going by what the 'pros' told me.

Again, apologies if this sounds brusque or whatever, but on the assumption that you were a student at the school at that time, it's perhaps understandable that the pros' may not have given a young pupil ALL of the right information....

 

Depends on circumstances, of course.........

[cedd]

I might add that pluggable dimmers (as used in my old school) can make life far cheaper for a budget-tied school by allowing the same dimmers to be used in 2 spaces. Assuming you can get around the manual handling problems, it means more money can be spent on lanterns and the rig itself. It also means, providing the correct supply can be found, an ad-hoc setup can be done in a sports hall for example with a portable rig. One set of dimmers, one desk, far more cost effective. I wouldn't however go as far as my old school went in sharing EVERYTHING between the hall and drama studio (on 2 opposite ends of the campus), lanterns, cables, dimmers, desk, the lot. It caused an awful lot of work!

[iamchristuffin]

I definately agree with that, but we already have 12 dimmer racks, 8 of which are 63A, and the other 4 are 32A, which is more packs that power available, so we're always fine for available channels in any of our 3 performing spaces, unless 2 or 3 shows are on at once, and then we're usually stuck for desks and profiles, as well as dimmers. We have enough desks for each venue, but I and the lighting guy in my year know the Frog much better than the Sirius 24 or the Strand MX48, so we use it whenever we can! I'm fortunate enough to go to a school that has good equipment, and enough of it to make at lest two shows look good (which, admittedly, can be done with very little), and the main thing we're wanting for is microphones - we have 2 (!)

[Brian]

Or if you want to stick with Zero88 get a mambo or leap frog. Same board but can control more intelligents.

Be careful. The Mambo is a very different desk, not having any individual channel faders.

[PDD]

Schools are not supposed to have 3 phase (415) running on lighting systems. By putting in hard wired dimmers they can some how spread the load over the dimmers to make it legal. (thats what one of the technicians form stage electrics told me anyhow)

Without meaning to add fuel to the fire, at my previous job, Stage Electrics more-or-less refused* to put in a mixed-phase patch bay (not necessarily a patch bay which could allow cross-phasing, but one which contained mixed phases in same casing, AFAIK was the reasoning). Whilst dubious of this requirement (there is apparently some new-ish regulation which advocates this return to split-phasing in patch bays), it suited our needs at the time so we went with hard-wired dimmers instead. The cost difference was minimal by the time you compared the cost of the dimmmers, or the cost of a decent phase-segregated patch bay or some such.

 

Having said that, at my present job when we get re-built, the number of proposed circuit outlets far outweighs a viable number of dimmers for the size of venue, and therefore I'm looking at a Powercon patch bay, similar to that built by Northern Light for the Young Vic (see L&Si March 07).

 

Back to the OP, I fully understand removing the patching element from school installations make it less complicated and less open to misuse, although as has already been mentiond it does mean dimmer packs cannot be portable between venues (although it doesn't sound like the OP needs this if they already have several packs) and it also makes it difficult to teach/learn the concept of patching without an example to hand.

 

* To be fair, I should add that Hawthorn were also reluctant, although would have supplied our initial requirements.

[Brian]

Whilst the requirement to keep phases several metres apart went out of the regulations a few years ago, all designers of electrical systems have a duty to ensure that the system they design is suitable for its intended use.

 

There is nothing wrong with a system designer deciding that for a school installation it is appropriate to keep phases separate.

 

Likewise, deciding that the risks involved with the use of the larger CEE17 connectors are too high is a reasonable judgement call.