I am doing a job at the mo, where gas bottles are installed outside. There three types of gas; Argon, Argon Carbon dioxide and Propane. The gas enters the building via copper piping. Do these pipes need to be bonded where they enter the building. One spark said we can cross bond off the 100mm x 100mm metal trunking. I said the gas should have its own dedicated 10mm earth from the main earth bar. Any thoughts please?
Earth bonding to gas bottles
- Thread starter adammid
- Start date
Help Support Talk Electrician Forum:
Would it be more dangerous to bond than not?
Why does this need bonding?
What detrimental effect could binding this have?
What advantageous effect could bonding these have?
Why does this need bonding?
What detrimental effect could binding this have?
What advantageous effect could bonding these have?
are the pipes entering the building extraneous?
Sidewinder- that's what I'm asking you. The gas is used for welding. The pipes are connected to gas bottles installed outside in cages. I would have thought that they are extraneous conductive parts but not sure if they are classed as extraneous. My thoughts were that if the welding equipment came into contact with the pipes and they were not earthed they could cause an explosion??
so why dont you test to see if they are extraneous, as per 7671?
Well it's very doubtful the Ar, or the Argoshield will explode unless they are subjected to significant heating or damage, as Ar is an inert gas.
Ar & CO2 mix, AKA Argoshield is an inert gas and a gas which is used in fire extinguishers mixed.
These cylinders will have relief valves also.
They are more at risk from falling over and cracking the valve off which at 300 bar will result in a missile travelling horizontally.
Propane is a different kettle of fish. Obviously this is flammable and explosive.
Now I don't know the site, I have not seen the install.
What welding equipment could come into contact with the cylinders?
I would expect the welding equipment to be located inside the building and the cylinders to be located outside the building.
Now, the next question is WHAT welding equipment, as the standards for the design and manufacture of welding equipment are not BS7671.
IF the welding equipment is Oxy-Propane then no risk, no electric involved!
What standard is the welding equipment manufactured to, I can't remember the numbers now, but App 87 does & I'm sure he will be along shortly.
Basically modern, or new electric welding sets, MMA, MAGS or TAGS are all now powered by isolating transformers, so the risk is?
Ar & CO2 mix, AKA Argoshield is an inert gas and a gas which is used in fire extinguishers mixed.
These cylinders will have relief valves also.
They are more at risk from falling over and cracking the valve off which at 300 bar will result in a missile travelling horizontally.
Propane is a different kettle of fish. Obviously this is flammable and explosive.
Now I don't know the site, I have not seen the install.
What welding equipment could come into contact with the cylinders?
I would expect the welding equipment to be located inside the building and the cylinders to be located outside the building.
Now, the next question is WHAT welding equipment, as the standards for the design and manufacture of welding equipment are not BS7671.
IF the welding equipment is Oxy-Propane then no risk, no electric involved!
What standard is the welding equipment manufactured to, I can't remember the numbers now, but App 87 does & I'm sure he will be along shortly.
Basically modern, or new electric welding sets, MMA, MAGS or TAGS are all now powered by isolating transformers, so the risk is?
Hi Paul,
Years ago was it BS 638?? been superceded lots of times now though!!! BS EN 60974 ????
john...
---------- Post Auto-Merged at 21:39 ---------- Previous post was made at 21:33 ----------
Errrm, if you do not know how to test if they are extraneous, you should not really be doing the job....
What is the definition of "extraneous" "Liable to introduce a potential, generally earth potential blah blah"
Measure the resistance between them and the MET More than about 25,000 ohms to 50,000 ohms depending on circumstances and they are NOT extraneous, just bits of metal.....
john..
Years ago was it BS 638?? been superceded lots of times now though!!! BS EN 60974 ????
john...
---------- Post Auto-Merged at 21:39 ---------- Previous post was made at 21:33 ----------
Errrm, if you do not know how to test if they are extraneous, you should not really be doing the job....
What is the definition of "extraneous" "Liable to introduce a potential, generally earth potential blah blah"
Measure the resistance between them and the MET More than about 25,000 ohms to 50,000 ohms depending on circumstances and they are NOT extraneous, just bits of metal.....
john..
Just checked & 60974 seems the relevant standard App87, though there are SEVERAL sections!!!
- Joined
- Mar 28, 2008
- Messages
- 14,509
- Reaction score
- 1,187
Better look here for an electrician who can come and test it for you....
http://www.talk.electricianforum.co.uk/directory-uk-qualified-electricians-electrical-contractors-find-your-local-electrician/2370-find-your-local-electrician-here-list-uk-qualified-electricians.html
headbang
Special location- there are lots of sparks on site who can do it. I'm part of the clients team. Was just making enquiries to throw at the sparks when they reg to get out of doing it. You say BS 60974 will tell me what is needed then?
App87- if they are just bits of metal as you put it and not classed as extraneous conductive parts why then is it necessary to bond an incoming water pipe, when it enters the building in plastic and then changes to copper. Why do you still have to bond after the stop tap? Surely you are saying it's just a bit of metal as its not liable to gain earth potential. Also why do you still need to bond oil when it can enter the building from an outdoor oil tank and the oil pipe has been run above ground to the house. Are you saying then that the oil pipe is just a bit of metal and does not need bonding. Gas is explosive and whether or not the pipes are in the ground if a live conductor comes into contact with one of these pipes then 'bang' or an I missing the point??
App87- if they are just bits of metal as you put it and not classed as extraneous conductive parts why then is it necessary to bond an incoming water pipe, when it enters the building in plastic and then changes to copper. Why do you still have to bond after the stop tap? Surely you are saying it's just a bit of metal as its not liable to gain earth potential. Also why do you still need to bond oil when it can enter the building from an outdoor oil tank and the oil pipe has been run above ground to the house. Are you saying then that the oil pipe is just a bit of metal and does not need bonding. Gas is explosive and whether or not the pipes are in the ground if a live conductor comes into contact with one of these pipes then 'bang' or an I missing the point??
App87- if they are just bits of metal as you put it and not classed as extraneous conductive parts why then is it necessary to bond an incoming water pipe, when it enters the building in plastic and then changes to copper. Why do you still have to bond after the stop tap? Surely you are saying it's just a bit of metal as its not liable to gain earth potential. Also why do you still need to bond oil when it can enter the building from an outdoor oil tank and the oil pipe has been run above ground to the house. Are you saying then that the oil pipe is just a bit of metal and does not need bonding. Gas is explosive and whether or not the pipes are in the ground if a live conductor comes into contact with one of these pipes then 'bang' or an I missing the point??
The current edition of the regs says you may not have to bond.
The current edition of the regs says you may not have to bond.
Can you tell me where it says this in the regs? And what do you mean 'may not' have to bond? What are the deciding factors?
Do you mean if the circuit is protected by rcd then the pipe won't need bonding? if the live conductor touched the gas pipe the rcd would trip? What about lighting circuits that are not protected by rcd? If one of those live conductors touched the pipe then 'bang' if the pipe is not earthed as the lighting circuits are not protected by rcd??? Whether or not circuits are protected by rcd, incoming services still need bonding, or am I wrong??
Do you mean if the circuit is protected by rcd then the pipe won't need bonding? if the live conductor touched the gas pipe the rcd would trip? What about lighting circuits that are not protected by rcd? If one of those live conductors touched the pipe then 'bang' if the pipe is not earthed as the lighting circuits are not protected by rcd??? Whether or not circuits are protected by rcd, incoming services still need bonding, or am I wrong??
gavindrummond
Senior Member
I been a welder for 9 yrs the bottles were always kept outside in a secure lock up. When you needed a bottle you simply got one and fitted it onto the back of the welder via a chain.
I am doing a job at the mo, where gas bottles are installed outside. There three types of gas; Argon, Argon Carbon dioxide and Propane. The gas enters the building via copper piping. Do these pipes need to be bonded where they enter the building. One spark said we can cross bond off the 100mm x 100mm metal trunking. I said the gas should have its own dedicated earth from the main earth bar as its an incoming service. If a live conductor comes into contact with the pipe then potentially 'bang'! Any thoughts please?
Ha ha,
Well, with that attitude you will find no-one will advise you now.. and take it from me, there are people on here that are involved with actually WRITING the regs....
Still, just thought i would point out that you have very little idea as to what needs bonding and why..
The only things that need bonding are EXTRANEOUS ones, but trouble is, you do not have any idea what "extraneous" means.
Just to add to the fun, i will point out that a metallic item COULD in some circumstances be considered extraneous, even though wholly contained within a buildings equipotential zone, merely because it enters a "special location" from another location.
Have fun!!!!!
john....
Well, with that attitude you will find no-one will advise you now.. and take it from me, there are people on here that are involved with actually WRITING the regs....
Still, just thought i would point out that you have very little idea as to what needs bonding and why..
The only things that need bonding are EXTRANEOUS ones, but trouble is, you do not have any idea what "extraneous" means.
Just to add to the fun, i will point out that a metallic item COULD in some circumstances be considered extraneous, even though wholly contained within a buildings equipotential zone, merely because it enters a "special location" from another location.
Have fun!!!!!
john....
- Joined
- Nov 19, 2010
- Messages
- 241
- Reaction score
- 0
Bond the change in your pocket as well
App87, I have not by any means tried to claim I did know what needed bonding. It is obviously a confusing subject and that's why I looked to the experts for advice. It's not extraneous but the pipe contains explosive gases and if it comes into contact with a live conductor 'bang'. Surely it needs binding?
Similar threads
- Locked
