Extension strip / socket

Freebird

Eggman said:

scrumhalf said:

gringopig said:

Joule find out in a second...

Absolutely. Resustance is futile.

Your electricity jokes are shocking...

As long as nobody gets hertz.

ICBM

I think we farad enough of this.

ICBM

More seriously, you don’t need anything fancy. A good well-made standard extension is fine - robust and safe is all you need.

An RCD isn’t necessary in any modern house because the distribution unit has them on the individual circuits, although it might be a good idea if you’re playing somewhere you’re not sure of. But be aware that they don’t lift the earth connection so they don’t guarantee safety - the biggest risk when playing an instrument is a shock via the earthed strings from some other source, typically a mic on a different supply.

Simon_M

ICBM said:

But be aware that they don’t lift the earth connection so they don’t guarantee safety - the biggest risk when playing an instrument is a shock via the earthed strings from some other source, typically a mic on a different supply.

This is exactly why the regulations prescribe RCD protection for all sockets in theatres/shows/concert halls etc... One of the most common sources of dangerous touch voltages is lighting faults - old, poorly maintained and rarely inspected lights in a venue; fault occurs and earthed metallic casings become live; truss it is connected to becomes live and all other truss it is attached to; performer touches truss with one hand and any other earthed metallic part with the other (like the strings on a guitar where the amp has the ground contact connected directly to the earth of the installation - not all amps work like this) and gets a belt right across the ticker. In old venues where RCDs aren't fitted and the installation isn't well maintained this is probably an instant death scenario.

Earth faults are surprisingly common in these environments, partly because of the total bodges musicians and their 'technician' bring into the venues but also due to the lack of proper maintenance in these locations. There's also so many rumours flying around like 'RCDs change the sound of my amp' (which is bollocks of course) which means we end up with people bypassing safety devices! As the onsite electrician I have had to take stuff off musicians so many times because it is a shock or fire risk!

There's an entire set of British Standards relating to this sort of installation but I've rarely ever found a theatre spark who knows about them, never mind actually owning a copy!

Anyway, minor rant over.

Hootsmon

ICBM said:

More seriously, you don’t need anything fancy. A good well-made standard extension is fine - robust and safe is all you need.

An RCD isn’t necessary in any modern house because the distribution unit has them on the individual circuits, although it might be a good idea if you’re playing somewhere you’re not sure of. But be aware that they don’t lift the earth connection so they don’t guarantee safety - the biggest risk when playing an instrument is a shock via the earthed strings from some other source, typically a mic on a different supply.

John is there anything that guarantees safety from the deadly guitar and other source mic ?

ICBM

Simon_M said:

like the strings on a guitar where the amp has the ground contact connected directly to the earth of the installation - not all amps work like this

Not all, but those that don't are very rare - the only ones I know of are some modern solid-state amps such as Roland Cubes. All valve amps and most analogue solid-state amps I know of are earthed.

There are some others where the electrical ground is lifted slightly from the mains earth to minimise hum loop problems, but there's still a low enough resistance between the two that it doesn't help (typically 10 ohms).

Simon_M said:

Earth faults are surprisingly common in these environments, partly because of the total bodges musicians and their 'technician' bring into the venues but also due to the lack of proper maintenance in these locations. There's also so many rumours flying around like 'RCDs change the sound of my amp' (which is bollocks of course) which means we end up with people bypassing safety devices! As the onsite electrician I have had to take stuff off musicians so many times because it is a shock or fire risk!

Exactly - the most common being lifting the earth connection to break a ground loop, rather than doing it properly in the signal path. I have completely lost count of the number of amps and effects units I've repaired and had to re-connect the earth. I'm sure it won't have made me popular with some owners either! But tough...

Likewise replacing dangerous old mains connectors like Bulgins with modern IEC ones. A lot of vintage amp owners really don't want this done because they think originality is more important than safety or reliability - which is fine, I just won't work on your amp... and it will be returned with the plug removed.

Simon_M

hootsmon said:

ICBM said:

More seriously, you don’t need anything fancy. A good well-made standard extension is fine - robust and safe is all you need.

An RCD isn’t necessary in any modern house because the distribution unit has them on the individual circuits, although it might be a good idea if you’re playing somewhere you’re not sure of. But be aware that they don’t lift the earth connection so they don’t guarantee safety - the biggest risk when playing an instrument is a shock via the earthed strings from some other source, typically a mic on a different supply.

John is there anything that guarantees safety from the deadly guitar and other source mic ?

Proper electrical separation between line voltage and signal voltage using a suitable and reliable transformer will provide a high level of safety. Ensuring all equipment is properly earthed (bonded) and that the circuit protective conductor contact of any connectors between the fixed installation and your gear is reliably connected to earth. Having the correct low-voltage (mains) fault protection will pretty much remove all shock risk assuming it is well maintained and checked. As a musician you can't really check most of this so you kind of have to assume that the venue is taking safety seriously. You could always provide your own distro with with built in RCD protection but this still relies on all the correct earthing and bonding in place on the fixed installation side.

@ICBM will know a lot more about the inner workings of appliances and assemblies as I mostly work on fixed and temporary installations and rarely work on appliances.

ESBlonde

Get a mains tester device. They are about a tenner from DIY stores. Plug it in and get the correct reading on the socket before anything is connected. If the socket fails the test Tape over it and inform management. Cheap 4 socket bars can work, again test before use. The worst aspect of cheap sockets is usually the pin grips get weak and then heavy bass vibration or kick drum will cause a rhythmic arc/buzz noise. You can unplug, open the unit and pinch the gripper tounges together but they are cheap enough to toss and replace from the big supermarkets. one more thing to have a spare of.

Simon_M

ESBlonde said:

Get a mains tester device. They are about a tenner from DIY stores. Plug it in and get the correct reading on the socket before anything is connected. If the socket fails the test Tape over it and inform management. Cheap 4 socket bars can work, again test before use. The worst aspect of cheap sockets is usually the pin grips get weak and then heavy bass vibration or kick drum will cause a rhythmic arc/buzz noise. You can unplug, open the unit and pinch the gripper tounges together but they are cheap enough to toss and replace from the big supermarkets. one more thing to have a spare of.

This is good advice. Having equipment PAT tested isn't a bad idea either (assuming whoever does the testing does it properly!).

EDIT: https://www.screwfix.com/p/lap-ms6860d-socket-tester/91596

The tester won't tell you if the earth is good or not (or earth-neutral reversal) but it will at least tell you that there is something connected to the earth contact.

ICBM

Simon_M said:

hootsmon said:

John is there anything that guarantees safety from the deadly guitar and other source mic ?

Proper electrical separation between line voltage and signal voltage using a suitable and reliable transformer will provide a high level of safety. Ensuring all equipment is properly earthed (bonded) and that the circuit protective conductor contact of any connectors between the fixed installation and your gear is reliably connected to earth. Having the correct low-voltage (mains) fault protection will pretty much remove all shock risk assuming it is well maintained and checked. As a musician you can't really check most of this so you kind of have to assume that the venue is taking safety seriously. You could always provide your own distro with with built in RCD protection but this still relies on all the correct earthing and bonding in place on the fixed installation side.

That's the fundamental problem - your own gear can be as safe as houses and you're still at the mercy of something elsewhere in a venue. Luckily electrical standards are much higher now than they were 20 or 30 years ago, which is something to be thankful for.

I am a bit paranoid with my own gear - having once got a 'cross wiring' shock at a venue. Admittedly this was in the bad old days before RCDs on all distribution boxes. I disconnect the string ground from my guitars/basses and fit a high-voltage cap in series with it. This maintains the noise suppression while isolating the strings from the direct connection to the earth. It's not foolproof though - you could still get a shock from any other metal parts that are still directly grounded - pickup covers, metal control plates etc - and from the jack plug. But I think it's still better than nothing, and a lot simpler and cheaper than an isolating transformer.

But don't worry *too* much - you'd be pretty unlucky to get a shock in any decent UK venue now, if your gear is properly checked or certified. Don't feel it's an imposition or 'nanny state' rules to have it properly tested, if you're not sure - the idea is to not die.

Of course if you want to be truly safe on stage, just use wireless for both the guitar and the mic...

HAL9000

Eggman said:

scrumhalf said:

gringopig said:

Joule find out in a second...

Absolutely. Resustance is futile.

Your electricity jokes are shocking...

But at least they're current...

Gassage

www.olson.co.uk

Rocker

Yes @hootsman, wireless and you have no direct physical connection to your guitar amp.

OP, keep in mind that the fuse in the plug top is there to protect the cable and equipment. It does not protect you from receiving a shock if something goes wrong in the equipment.

kt66

With my Audiophile hat on I can tell you the strips without switches sound better
If you're near Islington pop to Grahams HIFI and get one of the blocks they make themselves. ps not silly Nordost money.

fretmeister

I've got these

https://www.amazon.co.uk/Duronic-ST12B-Extension-Engineered-protected-Black/dp/B005191K54/ref=sr_1_1?ie=UTF8&qid=1544634571&sr=8-1&keywords=duronic+st12b

Seem to work well.

Lestratcaster

I just an Argos cable 4 socket reel thing, its worked for me for the last 5 years though I should probably get a 6 way strip power thing. Usually at shows there's good supply of 4 ways though.

Also is it bad to plug an extension into another, and at some gigs I've seen people, another? Wouldn't it cause overheating?

rico

Gassage said:

www.olson.co.uk

The most visitor-unfriendly website I have visited in a while! Seems to have some good stuff when eventually get to what you're after though. What do you have from there?

Simon_M

Lestratcaster said:

Also is it bad to plug an extension into another, and at some gigs I've seen people, another? Wouldn't it cause overheating?

The short answer is ‘depends’. If you want to daisy chain two extensions together to plug in your amp, a couple of pedal supplies, your phone charger, a couple of small led lights, your active monitor, wireless transmitter you’ll (EDIT: probably) be fine. Don’t plug heaters in though.

Longer answer:

All power strips complying to the relevant British Standards (i.e. anything you buy in a UK shop/supermarket/Argos but not some cheap shit you bought from eBay China or Alibaba) should have a fuse in the plug protecting the cable and anything plugged into it. The cables and contacts will also be manufactured to the right spec to stand the maximum potential current. Much kit we guitarists use doesn’t draw much current  so you’ll probably be okay. 

That said, if you don’t unreel your cables or run them where the heat can’t escape it’s very easy to overload them. A 13A fuse doesn’t go bang at 13.1A, it actually takes nearer 20A to go
bang instantly and I could easily draw 14A through a 13A fuse pretty much indefinitely. Anyone who has ever plugged two fan heaters into an extension cable will know the extension cable gets VERY hot. 

The recommendation for power cables at festivals/shows is to have them wired in rubber cables generally in a larger cross sectional area than used for a domestic cable to
avoid exactly this. We usually specify tougher plugs and connectors for the same reason.

If I’m wiring up a stage I usually have a circuit of plug boards chained together around the stage for the musicians to plug their guitar amps, keyboards whatever all on one 16A circuit. Separate circuit for monitors, separate circuit for front of house, separate circuit for lighting and a circuit for heaters too. I always use quality kit and not just Woolworths special £2.99 jobbo.

ICBM

It's also best to rig multiple extension cables in a 'tree branch' system not a 'daisy chain' if you can - ie connect one, as heavy-duty as you can find, extension into the wall, then plug four more extensions into that, and if necessary four more into each of those, *then* plug the equipment in at the far ends of all those... not a chain of extensions each with one more extension plugged into it along with three pieces of equipment. The tree-branch method minimises the extra loading on all the cabling except the first one.

We are fortunate to live in a country with the best electrical system in the world - as Simon_M says, as long as everything is to the correct spec and the plugs have the right fuse value for the cable then you can't dangerously overload anything without a fuse blowing.

I've also personally seen a coiled-up extension cable melt when a band - not one I was working for! - didn't understand that the rating is reduced when it's left on the reel... this is not an idle warning, it started smoking and when they tried to pull the cable out it was just a big sticky mess inside.

Hattigol

maltingsaudio said:

@gringopig sorry had my serious head on when I replied and didn’t read it as humour, no offence meant . I get a bit anxious when folks start discussing electricity distribution as I see so many dangerous ideas/ bodges at gigs and as the buck usually stops with me I tend to jump on everything.

Seems like you just got your wires crossed?