Bare 50Hz AC 3 Phase Bus bars...what is safe voltage to use

[ipf]

Sounds dicey to me. Not enough info and whiffs of DIY.

 

[StephenRowley]

What do mean for a art gallery display?

Is it for lighting?
Power items in Said display?

I'm intrigued

 

[ipf]

What do mean for a art gallery display?

Is it for lighting?
Power items in Said display?

I'm intrigued

Maybe it's just available...can't think of any other reason.

 

[ElectroChem]

I'm thinking some kind of silly interactive 'modern art' exhibit. "Grab the busbars, it's perfectly safe!" No thanks, I've seen the autopsy reports from electrocutions.

 

[Wilko]

For what it’s worth, Class lll appliance design might be of interest. A suspended bare cable light system might be designed for this class and they are usually 12V, supplied by certified isolation transformer etc.

 

[Darkwood]

I use exposed voltage parts on machines sometimes to ensure production stopped if the conductive part of the machine breaks and touches down... Basically I have a wire drawing machine and we fit a monitored copper ring to pass the wire through, if the wire breaks it touches the ring and shuts machine down.

I actually use a 2 stage isolation method here, I use a monitored 24v dc supply that powers a float level unit, that unit dishes our about 6v DC and I have thus a safe voltage at extra low voltage that even in component failure will not rise to any dangerous level.

I would not be floating any voltages for public interaction in excess of voltages you find in a typical household battery, also you need to ensure it is fail safe IE a failure of the component or device reducing the voltage could not inadvertently raise the potential to dangerous levels.

If you expand a little on what you are exactly trying to achieve here there maybe a better solution as in optical sensors etc that can safely mimic or achieve the same outcome needed, a little more expensive but can remove the need to energise anything and thus you can even use insulated materials and not expensive copper bars.

 

[treezleef]

Thanks, yes, its just to light up the multiple exhibits. 10kW worth of 40W LED lamps is required.
The bare aluminium bas bars will be overhead, so people can touch them but only if they reach up.
We will have signs up saying "don't touch the bus bars" and i assume that will get us through the regulations?
The bus bars are bare metal...not covered.
So up to 50VAC is OK?

Low voltage DC just means too much current for us.
The current in the bus bars cannot be limited...as it has to supply to all the 10kW of lamps.

 

[westward10]

You cannot use out of reach as a measure of protection notices or not.

 

[DPG]

You need to be careful with this one. 50V at high current will give a big spark.

Who is installing the switchgear?

 

[treezleef]

Thanks...switchgear?.....you mean the switch to the primarys of the 10kW three phase transformer?
Our electrical guy i presume is doing this.
I presume it will be a big contactor with a biggish manual lever and these arent that expensive i hope?

The Art Gallery contains high price exhibits and the general public are not allowed in......only film crews who are under strict supervision. We have staff working in the gallery...and they will be trained not to touch the bus bars so i presume since its a "controlled area" then we will be allowed to have bare 50VAC bus bars as described?

We have a prototype, and we can touch one of the bare bus bars (with isolated 40VAC in it at the moment) when its energised and it does us no harm (mind you we have rubber souled trainers on). Mind you, i've never tried grabbing one of the three phase bus bars with one hand, and another phase with the other hand.
What would this do, i dont want to find out.
Mind you, i have taken non isolated 240VAC from hand to hand before and it didnt kill me...but i could feel my pectoral muscles vibrating!...no pain though....i was trying to press some probes across the 240VAC, and the contacts were corroded, so i had to apply loads of pressure, and then my hands slipped...and zappppppp!

But i guess i want to know which regs apply to us.?..and how can you get a "clause" in those regs so you can do what we want to do (ie 50Hz AC in three bare bus bars)?