johnny2step Posted March 6, 2010 Share Posted March 6, 2010 Hi Guys, I came accross some Pulsar Rack packs today in a school. They have 6 channels with two 5amp sockets per channel. Each channel is coved by a 10amp fuse. I am struggling to understand how this is safe and why they were designed like this. In my mind the problem is that each 5amp plug/socket has the capability of drawing 10amps through the fuse without blowing. This is obviously double the amount of current a 5amp socket is capable of safely carrying. I am a qualified electrician and was wondering if any of you guys had some experience with these dimmers and could give me some advice. Thanks in advance,John Link to comment Share on other sites More sharing options...
jfroment Posted March 6, 2010 Share Posted March 6, 2010 Hi John Are you sure they are 5A sockets? The 5A per channel versions appear to only be avaliable hardwired. And I certainly haven't come across any with 5A sockets on. That said, I used to work in a venue that had 10A dimmer outlets to 5A tails in the grid which I do hope they have upgraded (or downgraded!) by now. I found this pdf that may help: http://www.pslx.co.uk/Datafiles/Pulsar/Rak...nstructions.pdf Best James Link to comment Share on other sites More sharing options...
J Pearce Posted March 6, 2010 Share Posted March 6, 2010 The high school I attended had (and still has) Pulsar Rakpaks with twin IEC outlets, but with a 5A fuse on each IEC outlet. Are you sure theres not an outlet fuse as well as a channel fuse? Link to comment Share on other sites More sharing options...
johnny2step Posted March 6, 2010 Author Share Posted March 6, 2010 Hi again, there are 4 rackpacks in total (all 4U in size): 2 of them with 6 channels each are hardwired to one 5 amp socket, each on the lighting bar. the other 2 have 12, 5amp sockets on the front of the rackpack each. (2 per channel) each channel being fused with a 10amp fuse. the rackpacks with sockets on the front provide patching for the other lighting bars. They are deffinatly 5amp sockets, on the front of the rackpacks and on the lighting bars, and the fusing is per channel at 10amps. I am right in thinking this is unsafe? any other views? Thanks again guys!John Link to comment Share on other sites More sharing options...
erik10_4 Posted March 6, 2010 Share Posted March 6, 2010 Won't attempt to answer OPs question but I can confirm 100% that Pulsar produced Rackpacks with 5amp sockets (2 per channel - a total of 12 in all). I can also confirm that they have a 10A channel fuse....I have 2 such Dimmer racks! Cant believe there is anything unsafe as Pulsar made loads of them. I'll be intersted to see technical answer. Link to comment Share on other sites More sharing options...
revbobuk Posted March 6, 2010 Share Posted March 6, 2010 A google search reveals that it is the 21117ST, and indeed that is how they were shipped. It's also not an answer, and I suspect that fitting a 5A fuse is the only certain way of sorting the problem - but comparing a 10A IEC connector and a 5A round pin - I know which I would consider more likely to handle 10A safely. And I know which I would rather wire up. But that's just an opinion, not a suggestion. Link to comment Share on other sites More sharing options...
erik10_4 Posted March 6, 2010 Share Posted March 6, 2010 Just had a quick look at my Pulsar Racks (the ones with 12 X 5 Amp sockets) and confirmed that each socket has a 5 Amp fuse, as well as each channel having a 10 Amp fuse (could post photo link tomorrow if that would help)....so mine are fine . I wonder therefore if OP has something different? Link to comment Share on other sites More sharing options...
adam2 Posted March 7, 2010 Share Posted March 7, 2010 Provided that the equipment is used sensibly I would not worry.Remember that the load should not exceed 5 amps per socket, probably a single 1K or smaller lantern in practice, therefore overloading is unlikely, provided that multiway adators are either prohibited or strictly controlled.In the event of a short circuit, the 5 amp plug and socket should easily handle enough current to blow the 10 amp fuse without danger. Remember that the then IEE regs used to permit of three sockets each of 5 amps, on a 15 amp radial circuit, and no one worried about that.AFAIK such an arrangement is still permitted, and is possibly becoming more common.Many bars, hotels, and office reception areas are now installing 5 amp sockets for the connection of table lamps etc. These are often on 15/16 amp circuits, 5 amp plugs being used to stop poeople unplugging the lamps in order to charge telephones or laptops.Some luxury homes are being equiped with 5 amp sockets, on 10 amp circuits, for connecting portable lights. These sockets are often controlled by lightswitches at the door, in order that the customer may readily turn a number of decorative lamps on/off without the labour of walking around the room. Link to comment Share on other sites More sharing options...
JimWebber Posted March 7, 2010 Share Posted March 7, 2010 I have come across about a dozen of these rackpacks in various places, and I too will agree with them having channel fuses at 10A, and two outlet fuses at 5A. HTH Jim Link to comment Share on other sites More sharing options...
dmxtothemax Posted March 8, 2010 Share Posted March 8, 2010 Hi Guys, I came accross some Pulsar Rack packs today in a school. They have 6 channels with two 5amp sockets per channel. Each channel is coved by a 10amp fuse. I am struggling to understand how this is safe and why they were designed like this. In my mind the problem is that each 5amp plug/socket has the capability of drawing 10amps through the fuse without blowing. This is obviously double the amount of current a 5amp socket is capable of safely carrying. I am a qualified electrician and was wondering if any of you guys had some experience with these dimmers and could give me some advice. Thanks in advance,JohnIf there is 2x5a sockets per channel, I can understand why there is a 10a fuse.In practice there is only a small danger.But if you are determined to make it idiot proof or 100% safe,you can change the sockets to 10a,or change the fuse to 5a.how ever the last option could cause fuse blows under some conditions. Link to comment Share on other sites More sharing options...
adam2 Posted March 8, 2010 Share Posted March 8, 2010 Another way of making it idiot resistant would to change all the standard 5 amp plugs, for ones that incorporate a fuse.Fused 5 amp plugs are rather rare but do exist and be ordered from most wholesalers, they fit standard sockets. They take a 5mm X 20mm minifuse, normaly sold in 1 amp, 2 amp and 5 amp ratings, though numerous other rattings exist.This would be fairly time consuming though, and the additional fuses have added another failure point, not worth it IMHO but perhaps worth considering if anyone insists. Link to comment Share on other sites More sharing options...
paulears Posted March 8, 2010 Share Posted March 8, 2010 The only reason schools adopted the 5A system was for safety (perhaps misplaced safety) so if this pack has 5A outlets and doesn't have proper rated fusing, that is not a good move. Is the socket panel separate? Maybe somebody retrofitted a 5 amp socket system to a pack originally fitted with hard wire or 15A? Pulsar wasn't one of the makes originally involved in school 5A systems - Maybe the old Strand/Furse/Green Ginger et al died and this was used as a replacement? Link to comment Share on other sites More sharing options...
revbobuk Posted March 8, 2010 Share Posted March 8, 2010 The original brochure is here which does show the 21117 variant with 2x5A sockets and one fuse. Link to comment Share on other sites More sharing options...
Neil Hampson Posted March 8, 2010 Share Posted March 8, 2010 The original brochure is here which does show the 21117 variant with 2x5A sockets and one fuse. The photo does however clearly show the two, 5A fuse holders next to each of the 5A sockets. In addition to the main 10A fuse per channel. Link to comment Share on other sites More sharing options...
johnny2step Posted March 8, 2010 Author Share Posted March 8, 2010 These packs deffinatly do not have those fuses next to each socket - they also let a lot more dated in comparison to those in that link. Do all agree that currently this is unsafe and these should be either upgraded in the appropiate way ie new dimmers and 15A Sockets or channel fuses downgraded to 5Amps. Thanks all,john Link to comment Share on other sites More sharing options...
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