Playing on the back of a moving vehicle

[skankdelvar]

Well, no one else has posted it so I suppose I'll have to. Best 'Back of a Moving Vehicle' promo video ever.

https://www.youtube.com/watch?v=ZDCs7ijNUVM

Edited March 11, 2015 by skankdelvar

[mcnach]

[quote name='phil.c60' timestamp='1425995477' post='2713184'] The answer is quite simple: just play in rubber gloves and wellies. [/quote]

wireless!

[chris_b]

Just ensure that a qualified electrician installs the system and the rig is properly PAT tested afterwards.

You've got more problems with motion, gravity and the weather. Make sure you have heavy weights to anchor the cymbals, something to hang on to when the driver does 90 degree turns at speed and stops on a 6p. Make sure there are rain proof overs for the instruments and gear.

Check that the guy organising the whole thing has PLI.

[chaypup]

[quote name='Dad3353' timestamp='1426020200' post='2713577']
One wonders how anyone ever gets to use a jenny, in any circumstances, without risking a fry-up..!

Your biggest problem, by far, is going to be trying to stand upright if the lorry has to accelerate, brake or turn at all. A bit like a cross-channel ferry in February. Bracing yourselves will be all the more difficult with both hands occupied by the bass..! Even at slow, carnival procession, speeds, you'll get a surprise, so be prepared to lurch towards something solid, if there is such a thing on a carnival float. Accidentally leaning too far over the back can be a thrill, too. The step is rather high. I've played drums on trailers before, it's not easy keeping the cymbal stands in place., even on a 'still' trailer. I hate to think how it could work without lashing absolutely everything firmly to everything else. Never mind the 'lecky shock stuff; work out how to keep your balance..!
I still say 'Mime'..!
[/quote]

The simple and quite obvious solution is to attach the bass to a stand which is fixed to the truck. The you simply get the driver to accelerate or brake depending on whether you need to play up or down the fretboard. With a bit of practice I would've thought you could get some otherwise impossible runs in.

[chris_b]

I'd be more worried that you're going to get an even 240v with no spikes.

Don't take your best gear.

[4-string-thing]

I'm pretty sure standing up on the back of a moving truck is illegal anyway, if it's on the public highway. So even if you survive the risk of shock, you stand (no pun intended) the risk of prosecution?

[KingBollock]

[quote name='phil.c60' timestamp='1426021377' post='2713595']


I always have a full English before I use a Jenny....or any other girl for that matter. It's the only way I can find the energy,
[/quote]
It's amazing how much a Donkey ride can take out of you, isn't it?

[Dad3353]

This may give you some idea of what you're letting yourself in for ...

http://youtu.be/fVLH69hE80s

Note the intensive use of scaffolding. There is a 'live' group shown (near the end...), as well as gogo pole dancers and twirlers..!

[Billy Apple]

Could a chain or some such chain like thing not be hung from the underside of the chassis to the road to create a ground?

[machinehead]

[quote name='Billy Apple' timestamp='1426074565' post='2714021']
Could a chain or some such chain like thing not be hung from the underside of the chassis to the road to create a ground?
[/quote]

Pointless I'm afraid. All that matters is the current flow in a fault condition. The fault current path must be such that it activates any safety devices so disconnecting the supply.

I've explained how to do this in a previous post in this thread.

Frank.

[Billy Apple]

[quote name='machinehead' timestamp='1426077814' post='2714076']
Pointless I'm afraid. All that matters is the current flow in a fault condition. The fault current path must be such that it activates any safety devices so disconnecting the supply.

I've explained how to do this in a previous post in this thread.

Frank.
[/quote]

So this would not earth the current then?

[DorsetBlue]

[quote name='skankdelvar' timestamp='1426043616' post='2713761']
Well, no one else has posted it so I suppose I'll have to. Best 'Back of a Moving Vehicle' promo video ever.

[url="https://www.youtube.com/watch?v=ZDCs7ijNUVM"]https://www.youtube....h?v=ZDCs7ijNUVM[/url]
[/quote]

Not sure, this one is close:

https://www.youtube.com/watch?v=6e5hRLbCaCs

[phil.c60]

[quote name='KingBollock' timestamp='1426070938' post='2713947']
It's amazing how much a Donkey ride can take out of you, isn't it?
[/quote]

There's always some ass ready to give you a going over, isn't there?

[Billy Apple]

[quote name='DorsetBlue' timestamp='1426086650' post='2714205']
Not sure, this one is close:

[url="https://www.youtube.com/watch?v=6e5hRLbCaCs"]https://www.youtube....h?v=6e5hRLbCaCs[/url]
[/quote]

Lucky that Ashdown rig didn't blow up

[machinehead]

[quote name='Billy Apple' timestamp='1426086327' post='2714198']
So this would not earth the current then?
[/quote]

I would think it unlikey due to the high impedence.

What you need to do is have your own isolated "earth" system which would, in this case, be the chassis of the generator. Whether or not you're connected to the ground (the actual soil of the earth) isn't important in this instance.

A ship for example, uses the steel hull as an isolated "earth" and monitors leakage to the hull/earth.

Frank.

[TimR]

[quote name='Billy Apple' timestamp='1426086327' post='2714198']


So this would not earth the current then?
[/quote]

Don't worry about 'earthing' the current.

You're trying to stop a dangerous voltage difference happening.

When a bird perches on a high voltage line it's voltage rises to be the same as the high voltage line. It's not a problem until it somehow manages to have one foot on the ground and the other touching the live wire. Which is impossible for the bird.

[Ancient Mariner]

[quote name='TimR' timestamp='1426092333' post='2714298']
Don't worry about 'earthing' the current.

You're trying to stop a dangerous voltage difference happening.

When a bird perches on a high voltage line it's voltage rises to be the same as the high voltage line. It's not a problem until it somehow manages to have one foot on the ground and the other touching the live wire. Which is impossible for the bird.
[/quote]

Exactly this. And if you're standing on the flat wooden bed of the truck, itself a good insulator, then it won't matter if the strings carry a potential difference of 240V because there's now way for the electricity to flow. IIRC the generators I've used on carnival floats in the past (designed for industrial use) all had RCCD circuit breakers built in.

Don't earth the genny in any way and all will be fine.

[spacey]

[quote name='Ancient Mariner' timestamp='1426095617' post='2714360']
Exactly this. And if you're standing on the flat wooden bed of the truck, itself a good insulator, then it won't matter if the strings carry a potential difference of 240V because there's now way for the electricity to flow. IIRC the generators I've used on carnival floats in the past (designed for industrial use) all had RCCD circuit breakers built in.

Don't earth the genny in any way and all will be fine.
[/quote]

If this were true, none of the equipment would work.

To be 100% Honest here, there is a very good reason only people who are "qualified" are allowed to mess with mains electricity and Gas.
You have either sat down, passed the exams and got your paper work or you have not.
There is no "I know enough to do this" .
My best advice is, ask the system is tested by a qualified papers holding electrician with a mains tester that will trip test the breaker system.
Or let them get another mug to do it.

Edited March 11, 2015 by spacey

[TimR]

[quote name='spacey' timestamp='1426098679' post='2714417']


If this were true, none of the equipment would work.

...
[/quote]

It's AC. The earth is for protection only. The earth is not a conductor.

[spacey]

[quote name='TimR' timestamp='1426100454' post='2714433']
It's AC. The earth is for protection only. The earth is not a conductor.
[/quote]

That back to where we started, it will have no earth and a live 240V AC.
If it pisses it down, unless the RCD system is tested and found to be working, the risk of a fry up is on the cards.
canal boats, birds on wires, ships at sea and it will be right everyone else does it, will not stop an accident, only a correctly tested system that passes the basics will.
Only an Electrician with testing qualifactions can safely make that call.

[TimR]

http://electrical.theiet.org/wiring-matters/39/portable-generators.cfm?type=pdf

[Phil Starr]

There's a lot of not too well informed advice here, well meaning enough. TimR has it about right especially with respect to earth. The important thing is to ensure all your equipment and the truck are at the same earth potential and that the gear you are using is all properly wired. An RCD will help but isn't foolproof.

The size of the generator has been mentioned. Add up the total wattage of your gear including any lights or other electrical equipment. Add another 50% and that should tell you the size of genny you need. I doubt the total of your gear is much over 1000W and even a quite small generator will be 2k so you shouldn't have a problem. the only problem I've had is that the voltage will fall before you over load the generator and this could cause some problems, hence the need to add 50%.

Generators are noisy, as are trucks, you might need more power to be heard than you expect. Without any reflecting walls and floors the bass in particular is lost, take your biggest rig for bass.

You really need to be supported if the truck stops suddenly and your gear needs to be strapped down too. No point in being held steady if you are hit by a flying 20lb bass amp! There are regulations about all this and you should ask the organisers about insurance, public liability may not cover you if you are part of the event.

In Somerset we have annual competitions for floats in all the local towns. PA systems are built into the trucks and tend to be rated in kilowatts. Anyone standing on the truck usually has a harness fixed to metal work and the floats are all inspected for safety, Marshalls ensure the trucks never exceed walking pace.

You can see some of the cages and harnesses on this https://www.youtube.com/watch?v=qaBHwy0DAIE&feature=youtu.be

[machinehead]

[quote name='Ancient Mariner' timestamp='1426095617' post='2714360']
Exactly this. And if you're standing on the flat wooden bed of the truck, itself a good insulator, then it won't matter if the strings carry a potential difference of 240V because there's now way for the electricity to flow. IIRC the generators I've used on carnival floats in the past (designed for industrial use) all had RCCD circuit breakers built in.

Don't earth the genny in any way and all will be fine.
[/quote]

Not correct I'm afraid, and potentially dangerous.

There is so much misinformation here that I'm not going to offer any more advice other than - get someone in who's a qualified electrical engineer.

I have over 40 years experience in electrical engineering, including a period lecturing, plus an electrical apprenticeship in 1973 and 20 years as a lead electrical engineer in the shipbuilding and the oil industries, working all over the world. I've designed many generation/power distribution systems.

In spite of this experience, what I've realised through this thread, is that it's just too dangerous to offer advice like this over the internet.

Get a qualified electrical engineer in.

Frank.

Edited March 11, 2015 by machinehead

[spacey]

[quote name='machinehead' timestamp='1426106574' post='2714564']
Not correct I'm afraid, and potentially dangerous.

There is so much misinformation here that I'm not going to offer any more advice other than - get someone in who's a qualified electrical engineer.

I have over 40 years experience in electrical engineering, including a period lecturing, plus an electrical apprenticeship in 1973 and 20 years as a lead electrical engineer in the shipbuilding and the oil industries, working all over the world. I've designed many generation/power distribution systems.

In spite of this experience, what I've realised through this thread, is that it's just too dangerous to offer advice like this over the internet.

Get a qualified electrical engineer in.

Frank.
[/quote]

+1

[TimR]

[quote name='machinehead' timestamp='1426106574' post='2714564']
...
[/quote]

Fair enough. But this is a very temporary (less than a day?) installation with a floating ground. Powering 3 small amplifiers.

A very common situation. It's all covered in the IET link I posted and there should be instructions with any generator.

The only possible difficulty I can see is tying the generator earth to the generator neutral.

There is no way to ground the generator earth and I don't see any practical or safe way of bonding the entire trailer, even if anyone considered it to be necessary.