Clarky Posted March 16, 2014 Share Posted March 16, 2014 (edited) Hi all, quick and easy question for anyone that isn't an electronics numpty like me. I need a kettle lead for my MarkBass combo (lost last one at a gig). Just went on to Amazon and there are loads of choices but the fuses vary from 5A to 13A. I have no idea which is right for a bass combo and the one on my PJB combo doesn't specify. So errr what do I need, pretty please? Edited March 16, 2014 by Clarky Quote Link to comment Share on other sites More sharing options...
flyfisher Posted March 16, 2014 Share Posted March 16, 2014 Kettle leads are interchangeable things and can therefore reasonable be expected to be used with all manner of devices. Furthermore, it is only UK plugs that are fused and the whole point of kettle leads is to allow devices to be used anywhere in the world, including countries where the mains lead will be unfused. Therefore, the device designers provide the appropriate fuse protection within their device and don't rely on uninformed users (no offence) to know what fuse to use. All of which is a long winded way of saying that 13A is fine. It will also mean the lead can be used for any other device as well. Quote Link to comment Share on other sites More sharing options...
Clarky Posted March 16, 2014 Author Share Posted March 16, 2014 I definitely fall into the camp of uninformed user! Many thanks. 13A it is then. Back to Amazon .... Quote Link to comment Share on other sites More sharing options...
HowieBass Posted March 16, 2014 Share Posted March 16, 2014 Have a look on the back of the combo to see what input power it draws (in watts), then divide that number by 240 (volts) and that gives you the value of the fuse required (in amps) but I'd guess it would be a 5amp fuse because my Genz Benz Contour combo can deliver 500 watts and that has a 5amp fuse in the kettle lead. Quote Link to comment Share on other sites More sharing options...
bassace Posted March 16, 2014 Share Posted March 16, 2014 But sometimes the amps have internal fuses, so if they blow there is a kerfuffle to get the innards exposed - not too clever on a gig. Which is why all my leads have 5a fuses in the plugs. And there is quite a disparity between amps re the fuse rating - what amps, slow blow/fast blow. So even though the fuse is accessible best to know exactly what fuse is needed and have one or two handy for replacement. And just to spoil the party, fuses don't often bow spontaneously; there could be a problem in the circuit being protected. I'm not a techie but someone with a few years of amp usage, that's all. Quote Link to comment Share on other sites More sharing options...
discreet Posted March 16, 2014 Share Posted March 16, 2014 (edited) I used 5A fuses with a Warwick amp and the thing kept blowing 'em on startup. Did a bit of research and switched to 10A, problem over. I've been using 13A lately without issue, but my new 500W GK amp (with GK-supplied mains cable) has a 10A fuse in it and I assume that Bob knows what he's doing... Edited March 16, 2014 by discreet Quote Link to comment Share on other sites More sharing options...
HowieBass Posted March 16, 2014 Share Posted March 16, 2014 [quote name='bassace' timestamp='1394971543' post='2397174'] But sometimes the amps have internal fuses, so if they blow there is a kerfuffle to get the innards exposed - not too clever on a gig. Which is why all my leads have 5a fuses in the plugs. And there is quite a disparity between amps re the fuse rating - what amps, slow blow/fast blow. So even though the fuse is accessible best to know exactly what fuse is needed and have one or two handy for replacement. And just to spoil the party, fuses don't often bow spontaneously; there could be a problem in the circuit being protected. I'm not a techie but someone with a few years of amp usage, that's all. [/quote] +1 to this, better the fuse to blow in the kettle lead before an internal fuse first but whichever did it'd mean the unit needed looking at. The very reason we have different value fuses is that they are rated for the demands of the equipment when running in normal safe operation. Quote Link to comment Share on other sites More sharing options...
BigRedX Posted March 16, 2014 Share Posted March 16, 2014 As flyfisher says the fuse in the mains lead is there to protect the mains lead and the fuse in the amp is there to protect the amp. Quote Link to comment Share on other sites More sharing options...
Clarky Posted March 16, 2014 Author Share Posted March 16, 2014 Thanks all for your advice and comments. I think the answer has to be 13A on the highly scientific grounds that this is what I have ordered! Quote Link to comment Share on other sites More sharing options...
HowieBass Posted March 16, 2014 Share Posted March 16, 2014 Don't worry you can just swap out that 13A for a 10A or 5A fuse any time you like. Quote Link to comment Share on other sites More sharing options...
Conan Posted March 16, 2014 Share Posted March 16, 2014 I got told off for calling them "kettle leads" a little while ago... Quote Link to comment Share on other sites More sharing options...
M@23 Posted March 16, 2014 Share Posted March 16, 2014 [quote name='Conan' timestamp='1394973747' post='2397201'] I got told off for calling them "kettle leads" a little while ago... [/quote] Haha, my old tech used to tell me off for calling them kettle leads too. Quote Link to comment Share on other sites More sharing options...
bassace Posted March 16, 2014 Share Posted March 16, 2014 They're kettle leads! Quote Link to comment Share on other sites More sharing options...
BigRedX Posted March 16, 2014 Share Posted March 16, 2014 [quote name='bassace' timestamp='1394975005' post='2397212'] They're kettle leads! [/quote] No they are not. I defy you to find any kettle that the mains lead from an amp would fit. Quote Link to comment Share on other sites More sharing options...
discreet Posted March 16, 2014 Share Posted March 16, 2014 [quote name='bassace' timestamp='1394975005' post='2397212'] They're kettle leads! [/quote] They're UK Mains to IEC C13 Power Leads! Quote Link to comment Share on other sites More sharing options...
Clarky Posted March 16, 2014 Author Share Posted March 16, 2014 Catchy Quote Link to comment Share on other sites More sharing options...
Clarky Posted March 16, 2014 Author Share Posted March 16, 2014 Funny isn't it. I used the wrong name yet everyone knew what I was referring to Quote Link to comment Share on other sites More sharing options...
JTUK Posted March 16, 2014 Share Posted March 16, 2014 I have many spare power leads and carry 13 amp and 5 amps as spares for them. I also have a Maplins type special fuse box with just about everything in it should the amps fuse go. But you should want to ask why a fuse would go in the first place. As for spare leads...every IT dept has a gazillion of them.. Quote Link to comment Share on other sites More sharing options...
flyfisher Posted March 16, 2014 Share Posted March 16, 2014 (edited) Is the amp fuse really internal and inaccessible? I'm pretty sure most gear that uses IEC (ok, kettle leads ) have accessible fuses, which would make sense considering that most of the world uses unfused mains IEC leads. The UK (and some of its old empire) is an exception in this respect. Edited March 16, 2014 by flyfisher Quote Link to comment Share on other sites More sharing options...
bassace Posted March 16, 2014 Share Posted March 16, 2014 Your probably right. I'm sure I remember an amp that was internally fused that I had once but right now can't find it. Can't stop now, off to find a kettle. Quote Link to comment Share on other sites More sharing options...
discreet Posted March 16, 2014 Share Posted March 16, 2014 [quote name='Clarky' timestamp='1394979279' post='2397259'] Catchy [/quote] I just call 'em 'mains leads'. Quote Link to comment Share on other sites More sharing options...
discreet Posted March 16, 2014 Share Posted March 16, 2014 I could murder a cup of tea. Quote Link to comment Share on other sites More sharing options...
TimR Posted March 17, 2014 Share Posted March 17, 2014 Any amp over 500w should have soft start on the input. When the amp is turned on you get a huge inrush current to the transformer, the soft start limits this current. On some amps (like the Warwick) that are close to 500W they don't always use them. Hence the need for a 10amp fuse. The 'internal' amp fuse will be a 3 or 5Amp slow blow fuse. The 'kettle' lead should ideally be a 10amp but 13amp is ok. Quote Link to comment Share on other sites More sharing options...
flyfisher Posted March 17, 2014 Share Posted March 17, 2014 (edited) . . . but, if you're in (say) France then the 'kettle' lead won't have a fuse at all, so it's clearly not an integral requirement for the safe operation of the amp itself, so I don't get the 'ideally should be 10A' thing and would suggest it's potentially confusing. Basically, any appliance with an IEC mains connector is a self-contained device and looks after its own fusing and other protection arrangements. An IEC mains lead is a completely separate electrical 'device' (so separate in fact, that it is PAT tested for safety) and in the UK the mains plug contain a fuse to protect that mains lead because it would be possible to draw 30A from most UK mains sockets before the consumer unit MCB trips out, and this would overload the IEC mains cable. Thus, in the UK, the IEC mains cable is protected by the plug fuse, which is why a 13A fuse is perfectly safe. In short, the fuse in a UK 'kettle' lead is not there to protect the piece of equipment that the 'kettle' lead is plugged into. Edited March 17, 2014 by flyfisher Quote Link to comment Share on other sites More sharing options...
Dad3353 Posted March 18, 2014 Share Posted March 18, 2014 In France, mains sockets are protected by a 16A fuse or circuit breaker in the fusebox. Up to a maximum of 8 sockets on one such fuse. Lighting is protected separately, by a 10A fuse or c/b. A 13A fuse in a plug is therefore somewhat redundant. A problem with a mains lead (chewed by a dog, slammed in a Transit door, 'spiked' by a kick drum...) would blow the fuse in the fusebox. I've never really understood why British plugs needed more protection than anywhere else in the world, but I suppose there's a historical reason. Quote Link to comment Share on other sites More sharing options...
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