What power lead for an amp?

[4 Strings]

Its called fuse discrimination.

[attachment=116673:Fuse discrimination.jpg]

The 30A fuse or breaker on your circuit board has to pass a lot more current without blowing than the plug on your amp. Also you'll need to run a short circuit through it a lot longer than through the fuse in your plug for it to blow. This is a good thing. You'll want it blowing as soon as poss though, hence the 'local' fuse.

[KingBollock]

I'm not sure how we can complain about [i]too much[/i] protection from electricity.

I did electronics in college where we had to go out on placements. I spent an awful lot of time around old people who liked to brag about the biggest electric shocks they'd had, which never made any sense to me. In all my life I've only ever had two, one from a phone line a few years before I even went to college and one from the mains a few years later, and I feel stupid for getting the second one, certainly not proud of it. Although it was a bloomin' stupid way to get it... I installed an IEC plug on a cable which I had left plugged in at the other end! I'd nearly finished before I actually got the shock, I had installed the wires but the earth tab popped up just as I was about to put the cover on and I got the shock when I pushed it back down.

[andyonbass]

The OP ought to get something like [url="http://www.powerconnections.co.uk/convert_eurotouk.htm"]THIS[/url] then you can just take it off when you do your european tour

Loads of 'em on ebay

Edited August 27, 2012 by andyonbass

[flyfisher]

[quote name='BRANCINI' timestamp='1346024643' post='1784318']
Not everything has an internal fuse. When did you last see one in a lawnmower or a vacuum cleaner or a kettle ?

The plug fuse will protect against a short if you damage the cable, old type round pin ( 5A or 15A) plugs were fed from the same 5A or 15A fuse in the consumer unit, as they are in europe. In the UK, 13A sockets on the ring main is usually fed from a 30A fuse or trip. Thats a lot of current for a 0.5mm mains flex which would probably glow red hot long before it blows the ring main fuse..
[/quote]

I agree with all that, though devices such as those you cite are unlikely to have IEC mains sockets but will have a UK fused plug directly connected. Also, that mains plug will be directly connected these days because it prevents laypeople from making understandable wiring mistakes when fitting their own plugs, which is fair enough, though it does nothing to prevent the same laypeople from fitting the wrong fuse.

The UK ring-main thing is also a good reason for a fused plug, but it still means that most European mains outlets are capable of providing 15A into a connected device via an un-fused mains lead, and 15A represents a hell of a lot of power.

[flyfisher]

[quote name='KingBollock' timestamp='1346028991' post='1784339']
I'm not sure how we can complain about [i]too much[/i] protection from electricity.
[/quote]

That's a fair point, though I'd suggest that a fused mains plug comes a fair way down the list of protective devices, which is probably why most countries in the world don't bother with them.

[xgsjx]

[quote name='KingBollock' timestamp='1346028991' post='1784339']
I'm not sure how we can complain about [i]too much[/i] protection from electricity.

I did electronics in college where we had to go out on placements. I spent an awful lot of time around old people who liked to brag about the biggest electric shocks they'd had, which never made any sense to me. In all my life I've only ever had two, one from a phone line a few years before I even went to college and one from the mains a few years later, and I feel stupid for getting the second one, certainly not proud of it. Although it was a bloomin' stupid way to get it... I installed an IEC plug on a cable which I had left plugged in at the other end! I'd nearly finished before I actually got the shock, I had installed the wires but the earth tab popped up just as I was about to put the cover on and I got the shock when I pushed it back down.
[/quote]

How did you manage to get electrocuted from a phone line?

Did you try sticking a RJ11 into the "live" orifice on a mains socket (pushing the earth down with a matchstick, no doubt)???

[Big_Stu]

[quote name='xgsjx' timestamp='1346013947' post='1784174']
Save money on fuses & just use a piece of 1/4" bolt. No fuses to blow!

Maybe I should pop that in the top tips section?
[/quote]

Years ago I was in a mates house who had done just that with his electric fire. We could smell burning & by the time we found what it was the cover of the plug was a white melted drool pouring down the wall. Much of the plug was glowing but it was still working.

[xgsjx]

[quote name='Big_Stu' timestamp='1346061730' post='1784570']
Years ago I was in a mates house who had done just that with his electric fire. We could smell burning & by the time we found what it was the cover of the plug was a white melted drool pouring down the wall. Much of the plug was glowing but it was still working.
[/quote]

Quality!

[BILL POSTERS]

[quote name='flyfisher' timestamp='1346056354' post='1784443']
I agree with all that, though devices such as those you cite are unlikely to have IEC mains sockets but will have a UK fused plug directly connected. Also, that mains plug will be directly connected these days because it prevents laypeople from making understandable wiring mistakes when fitting their own plugs, which is fair enough, though it does nothing to prevent the same laypeople from fitting the wrong fuse.

The UK ring-main thing is also a good reason for a fused plug, but it still means that most European mains outlets are capable of providing 15A into a connected device via an un-fused mains lead, and 15A represents a hell of a lot of power.
[/quote]

They were only examples, Kettle/Kettle lead, Lawnmower has a mains socket....

Agreed 16A is a lot, but still a reduced risk. a fuse will carry 70% over its rating before it blows, Picture this - the cable to a standard lamp in my house has a loop resistance of 10 ohms, so if the cable is shorted at the lamp end, it will draw 22 Amps, if there was no plug fuse, the ring main fuse wont blow till you draw 51Amps.

In the UK, your house just burnt down. In Europe, you blew the trip.

btw, you can feel a mild shock from a BT socket (about 50V) a wet finger across the wires is a good check to see if its connected.

[dincz]

[quote name='xgsjx' timestamp='1346061664' post='1784569']
How did you manage to get electrocuted from a phone line?
[/quote]

They used to send over 100V AC down the line to ring the bell. Enough to give you a nasty tingle!

Edited August 27, 2012 by dincz

[xgsjx]

[quote name='dincz' timestamp='1346064787' post='1784644']
They used to send over 100V AC down the line to ring the bell. Enough to give you a nasty tingle!
[/quote]

I did not know that! Shocking!

I've had a few 110v shocks & burns. All back when I was in my late teens/early 20s.

[Gareth Hughes]

But which lead is best for metal?

(In case no-one has said it)

[flyfisher]

[quote name='BRANCINI' timestamp='1346063308' post='1784615']
They were only examples, Kettle/Kettle lead, Lawnmower has a mains socket....

Agreed 16A is a lot, but still a reduced risk. a fuse will carry 70% over its rating before it blows, Picture this - the cable to a standard lamp in my house has a loop resistance of 10 ohms, so if the cable is shorted at the lamp end, it will draw 22 Amps, if there was no plug fuse, the ring main fuse wont blow till you draw 51Amps.

In the UK, your house just burnt down. In Europe, you blew the trip.
[/quote]

Agreed. [u]Given that UK mains outlets are usually 30A[/u] then a fused plug is a good idea, though it's all a bit arbitrary, though and even better idea might be to replace 30A fuses/trips in UK consumer units with 15A fuses/trippers, which would then - according to the European 'model' make the fuse in the mains plug unnecessary.

Getting a bit pedantic now though and I'm certainly not advocating bolts as fuses or even using 13A fuses for every mains plug, just trying to make the point that even the 'correct' fuses do not suddently render electrical things failsafe. And certainly not where shock hazards are concerned!

[xgsjx]

Well if you can't find a bolt to replace the fuse, then 3 matchsticks do a grand job of replacing the plug.

[pete.young]

[quote name='xgsjx' timestamp='1346066685' post='1784693']
I did not know that! Shocking!

I've had a few 110v shocks & burns. All back when I was in my late teens/early 20s.
[/quote]

In the UK, it's 48 V DC.

[dincz]

[quote name='pete.young' timestamp='1346084943' post='1785047']
In the UK, it's 48 V DC.
[/quote]

I was talking from UK experience - no idea what system they used or use here in CZ. 48V DC (or 50) is always present on the line. The 100+V AC (around 20Hz) was present only for ringing the bell. Don't know how it is now. I guess there aren't too many subscribers using old bakelite phones with electromagnetic bells so probably not necessary.

Edited August 27, 2012 by dincz

[barkin]

As far back as I can remember, ringing in the UK has always been 75V AC @25Hz

[KingBollock]

[quote name='xgsjx' timestamp='1346061664' post='1784569']
How did you manage to get electrocuted from a phone line?

Did you try sticking a RJ11 into the "live" orifice on a mains socket (pushing the earth down with a matchstick, no doubt)???
[/quote]
I'm not exactly sure... I was 15 and working in a Guitar shop and the phone line had snapped outside, not the main supply line, just a line running from that and into the shop. The boss asked me to fix it. I didn't even know there was electricity running through the line. I was standing on a stool, so I could reach the break, when a Police car stopped a couple of kids who had nicked a bike. I was watching them and not really paying attention to what I was doing when I got the shock. It was only 50v but I felt it.

[dincz]

[quote name='barkin' timestamp='1346093878' post='1785208']
As far back as I can remember, ringing in the UK has always been 75V AC @25Hz
[/quote]

You're probably right. I may have confused it with the Australian system.

[BILL POSTERS]

[quote name='dincz' timestamp='1346092178' post='1785182']
I was talking from UK experience - no idea what system they used or use here in CZ. 48V DC (or 50) is always present on the line. The 100+V AC (around 20Hz) was present only for ringing the bell. Don't know how it is now. I guess there aren't too many subscribers using old bakelite phones with electromagnetic bells so probably not necessary.
[/quote]

Thats how it was yonks ago when I worked on dial up CCTV kit, Old phones still work so I cant see it being any different now, Power, high ring voltage plus speech both ways on two very very long thin wires, Pretty clever cosidering it was designed at least 150 years ago.

Edited August 27, 2012 by BRANCINI

[xgsjx]

[quote name='KingBollock' timestamp='1346094901' post='1785223']
I'm not exactly sure... I was 15 and working in a Guitar shop and the phone line had snapped outside, not the main supply line, just a line running from that and into the shop. The boss asked me to fix it. I didn't even know there was electricity running through the line. I was standing on a stool, so I could reach the break, when a Police car stopped a couple of kids who had nicked a bike. I was watching them and not really paying attention to what I was doing when I got the shock. It was only 50v but I felt it.
[/quote]

Hehe. I never expected more than a couple of volts to be going through a phoneline. What an educational place BC is!
Quality story. I could only dream of working in a music shop when I was 15.

[barkin]

[quote name='BRANCINI' timestamp='1346099350' post='1785336']
Thats how it was yonks ago when I worked on dial up CCTV kit, Old phones still work so I cant see it being any different now, Power, high ring voltage plus speech both ways on two very very long thin wires, Pretty clever cosidering it was designed at least 150 years ago.
[/quote]

BT specs are pretty much all available online, as Suppliers Information Notes (SINs) at http://www1.btwebworld.com/sinet/

From memory, the relevant one is SIN351, which specifies 40-100V AC.

The only difference between now and as far back as I can remember, is that the ringing is no longer generated by the old electromechanical "ringing machines".

I'm sure Loz feels better for knowing that

[Lfalex v1.1]

[quote name='BRANCINI' timestamp='1345800822' post='1781648']
Cant remember the details, but theres some regulation about the length of mains cable supplied with electrical equipment not being more than 1.5 Metres as its a trip hazard.
[/quote]

It goes something like:

"Look, there's plenty enough trip hazards on the stage as it is. Pedal boards, Kick drum mics, instrument cables, monitors, singers. Why should we (the manufacturer) bear the cost of supplying you with a longer mains cable [i]just[/i] so you can reach the plug socket behind the bar...."

[bremen]

[quote name='Gareth Hughes' timestamp='1346068309' post='1784736']
But which lead is best for metal?

[/quote]

A lead lead!

[BILL POSTERS]

[quote name='bremen' timestamp='1346247769' post='1786970']
A lead lead!
[/quote]

Thats just for Heavy metal.