Enough Power?

[kmssounds]

Hi all!

I went to a gig last week and really noticed how many plugs I have got power all my equipment - worst thing was I have had a much larger install out before.

I was wondering how it could be calculated if you are using too much power from the mains? Or is the 240 enough?

I will list what I have on at a party....


6x Martin Mac 250's
1x 500mw laser
6x par 38's
2x projectors
1x 50 plasma
2x 42 plasmas
2x Crown XTi6000
1x Starcloth

then all the smaller bits like...

3x laptops
2x pioneer cdjs
EQ
mixer
5 x 19" monitors
Haze machines

think thats about it?????:eek:

[DJ Jules]

How many sockets do you normally plug all of that into??

It's easy enough to calculate the power drain, you just need to add up the wattages of all of the equipment to get a total (I.e 250w lighting fixtures x 6 = 1500w)


Julian

[Danno13]

Don't forget that discharge fixtures can draw about 4 x their normal current when the lamp strikes, so best to plug them in one at a time. Personally, if I was using that lot I would be asking for a high current outlet at the venue and be taking power distro so I'd have plenty of overhead.

[kmssounds]

How many sockets do you normally plug all of that into??

It's easy enough to calculate the power drain, you just need to add up the wattages of all of the equipment to get a total (I.e 250w lighting fixtures x 6 = 1500w)


Julian

as much as possible.... think we used 8 or so??

I do switch them all 1 by 1, blew to many fuses to make that mistake lol...

[Happy Jack]

Danno and Jules have covered it really, although I'd add that it is probably wise to ask the venue management what else is to loaded on the circuit you intend to use on the day of the show.

Also mentioned above, you can calculate out the average consumption by dropping in the values at nominal line voltage via a single 13a outlet and seeing if your equipment exceeds this, so

P = 230 * 13 = 2990w

Gives you a rough upper limit. Spreading the load as you have been reduces the demand on the single outlet, so is always recommended! And as Danno rightly says, it is the Mac's you'll have to watch.

In the absence of a 32 / 16 Ceeform power drop, I'd recommend a few Martindale CP501's in the gigbag to prove an 13a outlet.

http://instrotech.com/17th-edition-testers-socket-testers-c-21_32.html

Then something like the Pro Elec Power Meter to plug into the socket prior to loading it up to give you a readout of the current draw when it's all running.

We own a few and occasionally drop them in while we prep if we want peace of mind that opening up the amps isn't going to going to blow the 13a fuse in the plug top.

http://cpc.farnell.com/pro-elec/eme-1/multifunction-power-meter/dp/PL10053?in_merch=Featured%20Products&MER=e-bb45-00001001

Hope that helps.

[TONYTIGER]

Nothing to technical ,but a few pointers a 13 amp outlet will take aprox just over 3kw.
A Mac has a draw of 1.8 amps which is around 360w
Find out what all your fixtures draw and do some simple maths,remember to keep the sound on a separate circuit from your lighting.

sorry Jack got there first.

[Happy Jack]

...a 13 amp outlet will take aprox just over 3kw.

Don't be sorry, Tony, there's a good point there speaking about tolerance.

'Nominal' line voltage in this country since the EU harmonization is defined as 230v +10% −6%. It can and does fluctuate. Not wanting to take this OT with talk about voltage drop, sensitive equipment and inherently 'dirty' mains supplies, it's always best to allow yourself a big of 'wiggle' room just in case.

As always it''s a good idea to prove, to the best of your knowledge, that whatever supply you intend to plug into is fit for purpose.

[Ajaysdisco]

Well I would need to know the manufacture of the other stuff to find there power consumption but the Amps and the Macs are taking about 23A.
Considering a standard ring is rated to 32A, you are getting very close to the limit, don’t forget there may be other things on that ring.
With that amount of stuff I would start thinking about splitting it across three phases.

[Chris1984]

turning lights on one at a time to fit more on an outlet is very bad practice.

[DJ Jules]

turning lights on one at a time to fit more on an outlet is very bad practice.

Realistically, if you have 6 discharge fixtures at 360w each, and assume that they're going to take anything up to 1.4Kw/each when they're turned on, there's not a lot you can do unless you have a three phase (i.e. 64a+) power supply available (other than turning them on one by one, or leaving 4 at home!)

Julian

[Danno13]

Actually, being devil's adovcate I'm pretty sure alot of fixtures allow you to strike the lamps by DMX :) Didn't think of that earlier though!

[Ajaysdisco]

turning lights on one at a time to fit more on an outlet is very bad practice.

Not necessarily, the way they do it in industrial discharge lighting is use type C or D breakers. This gets over the inrush.
For example a 32A D will trip at 640A whereas a standard 32A B will trip at 160A
When using a standard ring you don’t have this luxury so switching in sequence is the next best option.



Realistically, if you have 6 discharge fixtures at 360w each, and assume that they're going to take anything up to 1.4Kw/each when they're turned on, there's not a lot you can do unless you have a three phase (i.e. 64a+) power supply available (other than turning them on one by one, or leaving 4 at home!)

Julian

:agree:

You can buy power switches that switch the power on in sequence so this is a known problem and there are products on the market to get over this.
Like this:
Link (http://www.studiospares.com/furman-ps-pro-e-ii-power-sequencer/invt/470810/?htxt=Y0HpSsZME3aQ7692RpvNzNLJedhjVgGR1vwQAYpK6HMG oAnJLVfHlv55K38tCX%2B2KTLpCeu4ZT6q%0Am9ndctRbkQ%3D %3D)
Otherwise you could strike using DMX as mentioned.

[Chris1984]

Not necessarily, the way they do it in industrial discharge lighting is use type C or D breakers. This gets over the inrush.
For example a 32A D will trip at 640A whereas a standard 32A B will trip at 160A
When using a standard ring you don’t have this luxury so switching in sequence is the next best option.


I am well aware of the different grades of breakers.
So in the event of a power cut and all the kit goes of and then power is restored quickly or a back up system kicks in your screwed because you are effectively overloading you power supply.
It is bad practice - we supply alot of power to alot of big events including many blue chip conferences and festivals. - if people do things like this then they dont get power - simples.

[Chris1984]

Realistically, if you have 6 discharge fixtures at 360w each, and assume that they're going to take anything up to 1.4Kw/each when they're turned on, there's not a lot you can do unless you have a three phase (i.e. 64a+) power supply available (other than turning them on one by one, or leaving 4 at home!)

Julian

not really and its 63a not 64.
When we do event power we dont find out what all the caterers need then not give them it and ask them to switch on one at a time.

I really cant believe we are having this conversation.

As Dan has sid you need a higher current outlet and some professional event style distro.

Lets do it properly and not bodge it.

[Solitaire Events Ltd]

...and let's not be too patronising if we feel we know better than others. :)

[Chris1984]

...and let's not be too patronising if we feel we know better than others. :)

didnt mean to come across as patronising but i cant see why we are having this discussion still.

I thought we were here to promote best practice, not to do things in a potentially dangerous way!

[Solitaire Events Ltd]

didnt mean to come across as patronising but i cant see why we are having this discussion still.

I thought we were here to promote best practice, not to do things in a potentially dangerous way!

True, but I thought I'd mention it as the more technical people on here seem to be getting a little that way recently. :)

[Happy Jack]

I thought we were here to promote best practice, not to do things in a potentially dangerous way!
It would've been nice to have heard from the OP, but I'd have assumed that given the selection of discharge source lighting the supply would be there. I gather that probably isn't always the case and is what prompted the suggestions.

While I totally agree with the promotion of best practice - ensuring an adequate supply is a part of that, and if the OP fails to factor this in that is his responsibility - dangerous? In what way? While expensive, the Furman unit Ajay suggested is, I feel, a perfectly acceptable addition to the rack in such conditions, making the most the supply you are 'given' rather than 'specify' even in the event of the power cut.

Would be nice to hear from the OP and the frequency he is met with 13a outlets despite supplying a bevy of Mac 250's.