Do I need a ground wire to bridge?

axisus

OK, so this is the mock up of my guitar build that I've shown before, do I need some kind of ground wire to the bridge for this kind of thing?

WezV

Yes

OilCityPickups

emphatically what @WezV says :-)

axisus

Ok ta. Presumably to the tune-matic? What's the purpose? I'm totally ignorant on this stuff.

octatonic

To ground the strings.

If you don't then you will be the ground when you touch the strings.

Electricity takes the quickest path to ground- the strings are quicker than you.

Under certain circumstances this is safer.

The rest of the time it is just lower in noise.

ICBM

No, it's more dangerous - it's a myth that it's for safety, it's for lower noise.

The danger is because with the strings grounded and you touching them, if you touch something else that's live with your other hand the current will pass through you to get to the earth. This is by far the greatest risk when playing a guitar, and how almost all electric shocks happen.

But you do need it grounded for noise. It's much easier to ground the Bigsby than the tune-o-matic, there's more area to trap the wire under so you don't need to fit it inside the body insert hole. Drill through from under the middle of the spring foot into the control cavity.

If you're really worried about the shock risk you can put a high-voltage cap in series with the ground wire where it connects to the pot or jack. That will keep the noise suppression but remove the shock risk, at least from the strings or trem arm - you could still get one from the controls.

WezV

yeah mainly noise/hum reduction

some guitars don;t have one, and you get a change in the hum when you touch the strings

you can ground the TOM or the bigsby.  I have grounded each string through ferrule before on guitars with graphtech bridges

no need to solder the wire to the bridge, it can just be trapped against it.  you don't normally need a separate bridge ground wire on a tele because the plate is connected to the pickups ground through the baseplate and screws

octatonic

ICBM said:

No, it's more dangerous - it's a myth that it's for safety, it's for lower noise.

The danger is because with the strings grounded and you touching them, if you touch something else that's live with your other hand the current will pass through you to get to the earth. This is by far the greatest risk when playing a guitar, and how almost all electric shocks happen.

But you do need it grounded for noise. It's much easier to ground the Bigsby than the tune-o-matic, there's more area to trap the wire under so you don't need to fit it inside the body insert hole. Drill through from under the middle of the spring foot into the control cavity.

If you're really worried about the shock risk you can put a high-voltage cap in series with the ground wire where it connects to the pot or jack. That will keep the noise suppression but remove the shock risk, at least from the strings or trem arm - you could still get one from the controls.

What about the scenario where you have an amp with a death switch in the wrong position and don't have a string ground?

ICBM

octatonic said:

What about the scenario where you have an amp with a death switch in the wrong position and don't have a string ground?

No real problem, if the strings aren't grounded you aren't connected to the amp chassis. If they *are* grounded, then if the amp chassis becomes live so do the strings, and the serious risk is if you then touch something else which is earthed and the current still goes through you to get there.

In any case, no amp should have a 'death switch' these days - certainly not in the UK or anywhere else with a proper earthed electrical system.

The only possible situation where having the strings grounded is safer is if the strings on the guitar themselves touch something live without you doing first, and even that is far less likely to kill you than becoming the current path between something live and something earthed.

Trust me, the string ground connection is dangerous and not safer. It's one of the main benefits of wireless systems.

octatonic

Thanks for the clarification- I've laboured under a misapprehension for about 20 years now.

Appreciate you taking the time to explain it.

axisus

As always, many thanks for the great knowledge people, much appreciated.

Sassafras

What's a 'death switch'?

Sounds rather sinister.

octatonic

It is a ground switch on some older (tweed/blonde) amps that switches in a .047 (I think) cap to minimise buzz.

If the component fails then it can lead to the chassis becoming live, which could mean the guitar is live and you get a fatal amount of electricity when you touch either the guitar or the chassis.

My 110v  '62 Bassman had it- it was removed before I got it though.

As I understand it was more of an issue in the US where they have two prong connectors.

Danny1969

That's the death capacitor really, loads of old amps had them in the US

Sassafras

Never knew that. So a silverface Princeton wouldn't have a death switch?

Danny1969

Sassafras said:

Never knew that. So a silverface Princeton wouldn't have a death switch?

This amp ? if so it's the switch labelled ground switch at the bottom on the US model

randomhandclaps

Sassafras said:

Never knew that. So a silverface Princeton wouldn't have a death switch?

Not unless you pissed off your local amp tech.

ICBM

An Export model - which almost all the ones you will find in the UK are - will have the switch fitted but not connected internally. Fender made Export models from the Blackface period onwards - easy to spot because they have a red voltage selector knob, which itself is now technically illegal and should be disabled internally, on the back panel. They will have a 3-wire earthed mains cable.

If it doesn't have the voltage selector it will need an external stepdown transformer, and you *should* have the 'death cap' removed - the switch can stay - and an earthed power cable fitted, although a lot of people don't.

It's wise to check. Last week I worked on an amp which had had a replacement UK-voltage mains transformer fitted internally, and the original and only 150V-rated US death cap left in place and functional. This is extremely dangerous. If the cap shorts the live to the chassis you could in theory get a fatal shock before the fuse blows - also contrary to popular myth, fuses don't save you from electrocution (they don't blow quickly enough) but are to prevent fires.

Sassafras

Thanks, my brother's looking after it for me so I'll have a look next time I'm over there. I do know it's got an earthed mains cable.

jd0272

I've run a wire from tone pot to Tele bridge. Not used it plugged in tho. Now thinking should I remove, cause I touch stuff and shit?

ICBM

jd0272 said:

I've run a wire from tone pot to Tele bridge. Not used it plugged in tho. Now thinking should I remove, cause I touch stuff and shit?

Not unless you want a load of noise.

The risk of electrocution is very small, almost vanishingly small with UK electrics these days, unless you play in really dodgy venues or outdoors at some event that's too small to have a professional company supplying the generator.

If you're not going to fit an isolating cap, leave the ground wire on.