plasma use outdoors

[Country Joe]

"I assume you have read 'The Dice Man' by Luke Reinhart?"


I suspect he has!
I also suspect Chunko' is now thinking "Don't get CJ started on this one"
Too late!!

All the Best,
CJ

 

[chunkolini]

Oh lordy.
Two 3's time for bed.

 

[Wedg1e]

I am sure we could build a device, just get two lumps of the right metal and hit them together hard enough.

A few years back on another forum, I let slip that we had plenty of DU (Depleted Uranium) lying around (well OK, locked up ) at work.
I was subsequently contacted by three people, two of whom had created new user accounts and had Hotmail addresses, asking if I could supply them with some DU as they were 'element collectors' .
I said OK, as long as they would take all the Co-60, Cs-137, Ir-192 and Yb-169 that was shielded by the DU

In the event it cost the company £60K to get rid of it all but that was a lot less than the fine for illegally transacting Radioactives...

 

[dannyp]

That was not true with my old Cebora. It did not need earthing to the work. And, while a plasma with a pilot arc might be different, the basic system is creating the arc in the nozzle and blowing the hot gas onto the work. If the -ve. was the work, then it would be an arc from the tip to the work. Something like a spark eroder.

like meany things then more than one way to go about buliding a plasma cutter.

i use a cebora plasma prof 55 quite a bit, that dosent need an eath connection but it dosent cut much without it. i have seen other plasma cutters advertised as full power "pilot" arc they didn't need the eat connected but the tip shrouds didn't last meany minutes with the eath off

 

[chunkolini]

Kemmpifrog
Book turned up today.
first impressions?
Decent size, 800 + pages.
Half way through the intro. Loving it.
Very grateful. I have been looking for 'The' book on this subject for years.

 

[KemppiFrog]

That's what you get for being alarmist on a plasma thread

 

[chunkolini]

I am not sure I was being alarmist, if I got the orgone energy accumulator overheated anything might happen.

 

[KemppiFrog]

I await a glow on the northern horizon...........

 

[lshigham]

Unless you use it in pouring rain (when the trip would probably go first) I can't see a problem. Quite the reverse, as the fumes are a bit chokey and best not breathed. I almost always used mine outside. New system is with water table and extractor fan. But big stuff still will be outside.
KF

Edit: The voltage is around 100v, so can be a risk if it passes through you to earth. The +&- are in the torch, the earth clamp is a safety thing. The easiest path for the volts is in the machine, so that will be it's first choice. I sometimes used mine without the earth connected(absent minded). Still here.... And never got a tingle.

I have when someone thought it would be amusing to fire up the plasma whilst I was moving the earth in a metal floored oven, it was painful but nowhere near as bad as a 240v belt

 

[visor_down]

Old thread I know but didn't see much point in a new one. I was trying to find out what risks were and came across this excerpt from a plasma manual.

Electricity
Unlike conventional welding equipment the voltage present at the torch tip when energized is very high presenting a risk of electrical shock or electrocution if care is not taken in use.
The torch tip and hose connection of the machine carry 200V DC and are pulsed with a striking voltage of around 3000V when the arc is struck.
Unlike normal mains electricity a.c. supplies this d.c. supply will cause muscle contraction rather than spasm and may cause the hand to lock onto the supply rather than being thrown off - if you come in contact with it.
Great care must be taken to ensure you do not come in contact with the tip, or any contacts on the machine whilst it is on. This machine must be earthed. The high power requirements of this machine are common with all plasma cutters. When set to 28A cutting current or below the machine can be used safely from a standard 13A

The part that concerned me more, is below.

Avoid physical contact with the cutting tip when the power is on. The tip will be at a potential of 240Vdc when the torch switch is activated, this reduces to approximately 120Vdc during the cutting process.
Both voltages can cause serious electric shock. T
The brass gas connection on the front of the unit is also at these potentials when the torch switch is activated and the mains supply is switched on. 2.3 Always turn the machine power off and remove the plug before servicing or changing the cutting head components.
When using the machine on site or outside ensure the grounding terminal on the back of the machine is connected to a safety earth. This will prevent any leakage current from the cutting circuit causing an electric shock to the operator.
A cable with a cross sectional area of 6mm2 is suitable for this purpose. Neither the torch lead or earth clamp are directly connected to the mains earth inside the unit although the unit case is itself earthed to the mains cable earth wire.

 

[Kent]

Makes Gas cutting sound far safer don't it just

 

[skotl]

...When using the machine on site or outside ensure the grounding terminal on the back of the machine is connected to a safety earth. This will prevent any leakage current from the cutting circuit causing an electric shock to the operator.
A cable with a cross sectional area of 6mm2 is suitable for this purpose. Neither the torch lead or earth clamp are directly connected to the mains earth inside the unit although the unit case is itself earthed to the mains cable earth wire.

I'm not sure that I'm totally convinced by this (where's brightspark or brokenbiker?).
It states that the unit case is earthed via the mains cable earth wire (and mine certainly is) so why would you also want a separate earth from the "safety earth" clamp on the back of the unit? And what's the point of using 6mm2 cable when the supply cable is likely no more than 1.5mm?

I presumed that the earth tab on the back of the unit was to star-earth it when used in conjunction with sensitive equipment, such as a CNC, rather than intended to be a safety earth.

 

[visor_down]

Makes Gas cutting sound far safer don't it just

Yeah sounds bloody lethal to me!

I'm not sure that I'm totally convinced by this (where's brightspark or brokenbiker?).
It states that the unit case is earthed via the mains cable earth wire (and mine certainly is) so why would you also want a separate earth from the "safety earth" clamp on the back of the unit? And what's the point of using 6mm2 cable when the supply cable is likely no more than 1.5mm?

I presumed that the earth tab on the back of the unit was to star-earth it when used in conjunction with sensitive equipment, such as a CNC, rather than intended to be a safety earth.

I thought exactly the same with regards to earth on the rear, the manual for my plasma states it is to reduce interference (this excerpt came up on a search and is not for my plasma). Like you say a sparks opinion would be good!

 

[tlovatt]

The casing of the machine has the potential to become live if there is a fault in the machine and hence is earthed using the earth connection of your electrical wiring.

The torch and return connections (with the return connection often called a ground or earth without being either of these) is a separate circuit and hence is not connected to the house wiring earth i.e. the voltage output from the plasma cutter is a floating voltage. In theory you can hold an earth and touch the tip of the plasma cutter (do not try this) and feel no ill effect as there is no circuit. When working outdoors it is recommended by manufacturers that an earth is introduced to the secondary circuit to prevent shock from leakage currents.

It is also worth noting that an RCD will not protect you from a shock off the output (secondary side) of a plasma cutter just as with almost any equipment that uses a transformer to delivery the power

 

[skotl]

Ah wait a minute... the earthing connector on the back of my unit (and, I think, on the back of visor_down's) is attached to the body, so probably is for anti-interference properties.

I wonder if the device referred to by the manual that you found online has an earth terminal that is insulated from the machine's chassis, but is hooked directly to the device's work clamp?

 

[Wendelspanswick]

Ah wait a minute... the earthing connector on the back of my unit (and, I think, on the back of visor_down's) is attached to the body, so probably is for anti-interference properties.

I wonder if the device referred to by the manual that you found online has an earth terminal that is insulated from the machine's chassis, but is hooked directly to the device's work clamp?

A few pieces of machinery I have had from China have included an earthing terminal and I guess that some mains supplies in China have an unreliable CPC (Circuit Protective Conductor) so are 'Earthed' locally.

 

[skotl]

My other thought, given the talk of using it outside, is that they may be considering when the unit is used with a generator and providing your own earth spike.

All in all, it seems like overkill for a properly wired UK device with a BS1363 plug...

 

[morssdn]

I would always use my plasma outside (with the unit itself inside the door), if used without fume extraction, as a couple of times inhaling the fumes when directly overhead the cutter has given me a stonking headache. With that in mind I now try to cut with the torch nozzle pointing away from me rather than downwards from my face. And I wear a 3M welding mask.

 

[Kent]

Have just been doing some research, apparently quite a few plasma plants being imported do not meet all the electrical safety requirements and can give the user enough shock to kill under the right or rather wrong circumstances. Its not my area so I wont pass further comment read it on Technical arc website

 

[ukracer]

I also use the plasma cutter outside only, but not when it is wet or rainy, then again, I don't do any sort of electrical work outside in those conditions.

Cheers

Ed.

I dont do ANY work outside when its raining. lol