BIG MAC Posted July 10, 2009 Share Posted July 10, 2009 Hi, I am trying to gather some information about power distibution with regards to Alphapack portable dimmers. I was wondering if anyone could help. I am helping out with lighting at our annual school show at a High School in Scotland. I am NOT an electrician and I am a pupil. I'm only trying to gather some info so as I can tell the teacher who is in charge of lighting (who should'nt be) how it should be done without blowing the lights up like he done last year! Here's the problem: We have two Strand Act 6's with 24, 15amp sockets in total. All of these sockets are occupied with all the lights on the stage and in the theatre. However, we have two Strand Quartet Profiles at the very back of the Theatre next to the lighting desk which have no power. Normally the school hire in 2 Alphapacks to run 2 Strand Cantata followspots off of. I know that they use one Alphapack for one followspot and he other Alphapack for the other followspot. I was wondering if you could plug the 2 followspots which are 1200w each into 1 Alphapack and plug that into a 13amp socket. I would use the other alphapack to run the 2 Quartets (650w each) and link the Alphapack into the chain from the desk. The chain would be --> Desk--> Alphapack for Quartets--> Strand Act 6 Dimmer 1--> Strand Act 6 Dimmer 2--> PSU Unit for Colour Scrollers--> Terminate Signal The Question is.... Would it be possible to run the two Alphapacks (with the information above) off of a double 13amp socket? Any help would be appreciated. Thanks Link to comment Share on other sites More sharing options...
Mr Steve Posted July 10, 2009 Share Posted July 10, 2009 (1200+650) / 230 = 8 and a bit Amps (power over voltage = current). So yes, although if you burn your school down it's not my fault. Link to comment Share on other sites More sharing options...
dmoffat Posted July 11, 2009 Share Posted July 11, 2009 Alpha packs are intended to have 13A protection built into them, so as such should not allow more than 13A to be drawn.1.2kw is about 5.2 amps, and as such two 1.2kw lamps on one alpha pack will be fine, so long as it is directly into the wall and not plugged into a 4-way.Two quartets will also be fine on a single alpha pack, but you need to ensure it is an alphapack2, or it may not be DMX able, just tell the hire company that you want to DMX the alpha packs, which may possibly cost a little more. So all in all it sounds entirely possible. Where about in scotland are you based? *NB* This all depends on what else is plugged into the ring main, and if the ring main is rather full then all of this may trip the 32A breaker. Link to comment Share on other sites More sharing options...
collism Posted July 11, 2009 Share Posted July 11, 2009 A good rule of thumb is that you can get up to 3000W of conventional lighting on to a single 13amp socket. Definitely make sure you check what else is on the ring main though! Link to comment Share on other sites More sharing options...
charl.ie Posted July 11, 2009 Share Posted July 11, 2009 Also note that a double 13amp socket is (normally) only rated for 13amps in total across BOTH PLUGS. Make sure they're on individual plugs, if that makes sense. Link to comment Share on other sites More sharing options...
dmoffat Posted July 11, 2009 Share Posted July 11, 2009 A good rule of thumb is that you can get up to 3000W of conventional lighting on to a single 13amp socket. Definitely make sure you check what else is on the ring main though! Really??Because I'm quite sure that 13 x 230 = 2990w so unfortunately you are 10w short of the 3k suggested.So the extra 10w won't always blow fuses, so can potentially be done, but really shouldn't be done. Link to comment Share on other sites More sharing options...
paulears Posted July 11, 2009 Share Posted July 11, 2009 I wonder if the stacks of OAPs with ancient 3K electric fires know this? Probably a good job very few (if any) outlets actually have 230V emerging from them. Link to comment Share on other sites More sharing options...
dmoffat Posted July 11, 2009 Share Posted July 11, 2009 Also note that a double 13amp socket is (normally) only rated for 13amps in total across BOTH PLUGS. Make sure they're on individual plugs, if that makes sense. I'm not entirely sure about that. If we are talking about a 4way plugged into a wall socket then yes, this is true, but if we are talking about a double wall socket then accoding to the blueroom wikiit's worth noting that most double sockets aren't rated to give 2x 13A. Typically, a double socket will be capable of delivering around 20A across the pair of sockets. which can be found here http://www.blue-room.org.uk/wiki/Lighting_...a_13A_socket.3F Link to comment Share on other sites More sharing options...
The Yellow Transit Posted July 11, 2009 Share Posted July 11, 2009 A good rule of thumb is that you can get up to 3000W of conventional lighting on to a single 13amp socket. Definitely make sure you check what else is on the ring main though! Really??Because I'm quite sure that 13 x 230 = 2990w so unfortunately you are 10w short of the 3k suggested.So the extra 10w won't always blow fuses, so can potentially be done, but really shouldn't be done.But not if its 13x240=3120w and now you are 120 w over Link to comment Share on other sites More sharing options...
PaulDF Posted July 11, 2009 Share Posted July 11, 2009 it's worth noting that most double sockets aren't rated to give 2x 13A. Typically, a double socket will be capable of delivering around 20A across the pair of sockets. which can be found here http://www.blue-room.org.uk/wiki/Lighting_...a_13A_socket.3FDecent quality double sockets may be able to deliver 20A continuous however cheapo ones might not like it. You also have to remember a ring circuit is designed to have the loading spread around it. Link to comment Share on other sites More sharing options...
robloxley Posted July 11, 2009 Share Posted July 11, 2009 Also note that a double 13amp socket is (normally) only rated for 13amps in total across BOTH PLUGS. Make sure they're on individual plugs, if that makes sense. MK Logic Plus standard double sockets are rated for 13A per socket outlet; other makes may vary. Link to comment Share on other sites More sharing options...
Andrew C Posted July 11, 2009 Share Posted July 11, 2009 3.1kW... Big fat hairy deal! A fuse will carry of the order 1/3 overload for a LONG time before it blows. Look up the graphs to see what I mean. Not suggesting designing to 4kW, but don't worry about 100W or so. Link to comment Share on other sites More sharing options...
JimWebber Posted July 11, 2009 Share Posted July 11, 2009 Just to muddy the waters a little bit, bear in mind that you are not connecting a 1000W lamp at all. You are connecting a 57.6 See Disclaimer Ohm load. If you connect that to a 240V supply, it will consume 1000 Watts (And draw 4.16Amps)If you connect that to a 230V supply, it will consume 918 Watts (And draw 3.85Amps) On the other hand, with a 52.9 See Disclaimer Ohm load: If you connect that to a 230V supply, it will consume 1000 Watts (And draw 4.34Amps)If you connect that to a 240V supply, it will consume 1089 Watts (And draw 4.5ish Amps) Thus any lamp you buy will be marked up with its power consumption (Watts) and its supply voltage. However, as Andrew C quite rightly points out above, these differences in current are pretty negligible as far as a 13A fuse is concerned. Disclaimer: Yes, I know that the resistance of a lamp is not constant, or even linear, but ohms law still rings true at any given instant in time, and serves to illustrate my examples. As is mentioned in the Blue Room on many occasions, if you do not know what you are doing, get someone who does! :unsure:) Jim Link to comment Share on other sites More sharing options...
collism Posted July 11, 2009 Share Posted July 11, 2009 Well considering that in the UK the mains is 230V that means that yes technically you might overload by 0.04A but two things: 1. I did say up to 3000W - any sensible configuration is going to leave a margin. For example I would do 5 x 500W Par cans giving 2500W. Apologies if I wasnt clear enough on that.2. A 13A fuse isnt going to blow on 13.04A which rounds to 13.0A to 1 d.p. in any case! Other posts are also right to suggest that caution needs to be taken with double sockets - I personally would limit the load to 13A over the two sockets and preferably use only 1 of the sockets. After all even if the ring main is 32A you would only need 3 separate sockets maximum to use all of this. Link to comment Share on other sites More sharing options...
Trunker Posted July 11, 2009 Share Posted July 11, 2009 Also note that a double 13amp socket is (normally) only rated for 13amps in total across BOTH PLUGS. Make sure they're on individual plugs, if that makes sense. Not what is being taught on the C&G 2330 course at college. These wall double sockets can comfetably take 20amps. Link to comment Share on other sites More sharing options...
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