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Topic Title: music studio
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Created On: 23 August 2013 02:14 PM
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 23 August 2013 02:14 PM
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beaver74

Posts: 361
Joined: 07 February 2007

hi guys

after a few pointers if possible.
I have been asked to make look at a property where they have at the moment got a few bands that use a few room, but it is protected by one circuit which is tripping out due to over current.

now while on site they will be providing a dedicated room and mixing room and wont to upgrade electrics.

I intend to price for the following

1 a 40A C type supply by means of a 3core swa using both armoured and internal earth separately as there is going to earth current of more than 10mA
2 install a local mains with RCBO protection to each circuit
3 install socket outlets with twin earth terminals.

I can not find a fill rate for cables in trunking so I would appreciate a nudge in the right direction.
any thing I have missed
cheers Beaver
 24 August 2013 09:40 AM
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DOUGIE1000

Posts: 4113
Joined: 13 August 2005

Your setup sounds ok. Can you use twin and earth instead of swa, twin and waeth might be better looking that swa indoors clipped direct.

-------------------------
Dougie
Power Plus Electrical.co.uk

My mission is to live as long as possible......so far so good!
 25 August 2013 11:55 AM
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Zs

Posts: 2627
Joined: 20 July 2006

hi Beaver,

I have been watching for replies to yours and waiting for the explosion but it hasn't come.

some questions first: your 40 Amp type C supply....do you mean a 40A type C in the main property DB feeding a sub-distribution board for the music part of the property?

Then, are you proposing multiple individual circuits for say the performing room and the mixing room? I don't quite get that from your post.

anyway, If that is the case then I agree with your type C at the origin of the music part of the building. Not enough info to confirm the Amps though.

I'd be inclined to have more than one circuit in each room. I would also anticipate that some bands will bring a stack of gear in with them and not just one amp per piece of kit. If it helps, my amp is about 40W and is usually used an a very calm setting. But I've measured leakage and current flow on it. it starts to go oingy boingy only if I mess with some of the daft noisy functions.There's a function on it called Brit Combo which makes a kind of Brian May sound and one called Gain which makes the noise that teenage boys who fancy themselves as rock-stars use. Both of those will probably get hammered in your studio.

I agree, in spades, with RCBO protection for the individual circuits. Especially because we 'do stuff' to our amps and you never know what kind of electrical modifications to kit have been carried out before they arrive in the studio. You are right that a single RCD would quickly get clogged up by electronic kit....It happened here at Zs towers recently while I was messing about with a borrowed volume pedal. Send tin foil .

As for the trunking issue; how many cables will there be in the most full section of trunking? Tell us what sizes they are and we'll look it up for you.. You'll be surprised how small trunking has to be.

What is the earthing arrangement of the property? is this professional or play?

I might be inclined to use singles and a CPC larger than the conductors but we need to know a bit more about the loads for that.

Zs
 26 August 2013 09:56 PM
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John Peckham

Posts: 7253
Joined: 23 April 2005

Radial circuits definitely not rings and keep the cable lengths as short as possible. Use FP200 to help stop the cable acting like aerials for noise. SWA to the building to supply a local DB with RCBOs for the sockets. Use the suppliers earth if there is one and add an additional earth electrode to the local consumer unit earth bar. Incandescent lighting generates less noise than fluorescent. Even with all that the guitar pick up coils may pick up a 50Hz hum.

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John Peckham

http://www.astutetechnicalservices.co.uk/
 27 August 2013 12:01 PM
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beaver74

Posts: 361
Joined: 07 February 2007

thanks for the replies sorry for the late reply but we have been away.
the music studio is to be in the same building as the mains supply. the swa is to exit property and clipped direct and then re enter the property, but does also have the advantage of being able to have the armouring used as a separate earth.
the 40A C type is the breaker protecting the submain.
the 2 rooms were to have 2 circuits in the large room and 1 in the mixing room.
the supply is PME.
I was thinking of 2.5 radials with the cable dropping from the ceiling once for each circuit and then horizontal to other socket. but I would like to give a separate price for a tidier job with trunking around the perimeter but I can not find a fill rate for trunking 1/2 rings a bell. if I go for a perimeter trunking singles can be used.
the studio is a well used youth club, but after Zs comments I think the submain may require an increased reting.
 27 August 2013 10:07 PM
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weirdbeard

Posts: 1372
Joined: 26 September 2011

Originally posted by: Zs


I agree, in spades, with RCBO protection for the individual circuits. Especially because we 'do stuff' to our amps and you never know what kind of electrical modifications to kit have been carried out before they arrive in the studio.


Just a thought, a studio is a commercial entity, so EAWR applies, it is not necessarily the electrical installers job to protect those modifiying their equipment against risk.
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