Explosion Proof Wiring Systems

[D Skelton]

If that was a dig at Eng I can assure you, he does know what he's talking about!

 

[pepparz]

If that was a dig at Eng I can assure you, he does know what he's talking about!

does he really? the release of pressure is a by-product of the explosion.the main point of flameproof equipment is to enable a explosion to occur in a enclosure,the gap is there to quickly extinguish and cool the explosion as to not ignite the surrounding atmosphere.

 

[D Skelton]

Disclaimer here: I am no expert as although I have seen and handled the stuff, I don't install it. Explosions however I know a fair amount about.

To control damage caused by an explosion you need to control the pressure (as you quite rightly stated is a by-product of..) created, hence why even though I don't install this type of wiring, what Tony and Eng (who are probably the most qualified sparks on here regarding this topic) are talking about makes far more sense to me than what you just said.

Chobham armour for example on Challenger 2 main battle tanks is specifically designed to absorb pressure created by a shell or rocket exploding on its surface and then to control and release that pressure laterally thus minimising damage caused to the main shell. If it's purpose was to instantaneously release that pressure then put it this way, I wouldn't be writing this now.

Although I digress slightly, the point I am trying to make is if you want to minimise the effect of an explosing having taken place within a wiring system or enclosure, it makes complete sense to me that the pressure created is released in a controlled manner.

 

[pepparz]

first of all thanks for telling us youve been in a tank rambo,but i dont think youre getting the point of flameproof equipment,your not trying to minimise the effect of an explosing having taken place within a wiring system or enclosure, but to prevent it igniting any gas or dust build up on the outside of a enclosure.if you disagree with me google it or go on the compex course, but lets not spend any more time on this ive some EXd glands to make off.

 

[D Skelton]

Yes, which can only be done in a controlled way, not instantaneously as you say. A part of me thinks due to your attitude and tone that you happen to be the one without any knowledge. You seem rather defensive for someone who supposedly has nothing to prove.

I'm also not quite sure I understand the 'Rambo' quip?

Hey ho though, you know everthing so I guess that makes everyone elses knowledge irrelevant. Sorry to have questioned you Your Grace!

 

[pepparz]

ive been working on a hazardous area site for the past 13 years 10 unaided so the statments i have made are correct so please dont embarrass yourself trying to disprove them.the rambo guip is in reference to your " Challenger 2 main battle tank ive been in the TA " bit.youre not in the army so let it go.

im not an expert on anything so ill only write what i know to be true.

its been fun, have a nice weekend.

 

[High Tower]

haha its really funny reading some of these old posts by people with limited knowledge trying to look like they know what their talking about.
a little knowledge is a dangerous thing!

Can you please explain why you have dug up a 2 year old thread with the purposes of using it to have a dig at other members?

 

[Silly Sausage]

Can you please explain why you have dug up a 2 year old thread with the purposes of using it to have a dig at other members?

He's an odd one this pepparz!

 

[D Skelton]

ive been working on a hazardous area site for the past 13 years 10 unaided so the statments i have made are correct so please dont embarrass yourself trying to disprove them.the rambo guip is in reference to your " Challenger 2 main battle tank ive been in the TA " bit.youre not in the army so let it go.

im not an expert on anything so ill only write what i know to be true.

its been fun, have a nice weekend.

I'm not embarrasing myself at all, I don't know you from adam yet you're on here digging at people so I'm perfectly within my rights to query your skills, as for whether or not I believe what you say that's an entirely different matter. Do remember however that people used to believe the world was square, turned out they were wrong. I think I'll stick to listening to what Tony and Eng have to say on the matter as I tend to have more time for what they say and plus, I know they know what they are talking about.

P.S. I've never been in the TA so don't quite know what you're talking about there???

 

[SPARTYKUS]

Gone quiet now a moderator's asked a direct question...!

 

[Toonlad]

ive been working on a hazardous area site for the past 13 years 10 unaided so the statments i have made are correct so please dont embarrass yourself trying to disprove them.the rambo guip is in reference to your " Challenger 2 main battle tank ive been in the TA " bit.youre not in the army so let it go.

im not an expert on anything so ill only write what i know to be true.

its been fun, have a nice weekend.

Lol nice to know it took you 3 yrs to make glands off.. speedy gonzalas, before you were unaided. lmao some achievement. Whahahahahahahahahahaha. Can you link up with specs and post some funnies, in the jokes section. Whahahahahahahaha

 

[monkeyelectric]

Yes, which can only be done in a controlled way, not instantaneously as you say. A part of me thinks due to your attitude and tone that you happen to be the one without any knowledge. You seem rather defensive for someone who supposedly has nothing to prove.

I'm also not quite sure I understand the 'Rambo' quip?

Hey ho though, you know everthing so I guess that makes everyone elses knowledge irrelevant. Sorry to have questioned you Your Grace!

I didn't understand the Rambo bit either! Rambo didn't need a tank, he was a one man army!

 

[Engineer54]

haha its really funny reading some of these old posts by people with limited knowledge trying to look like they know what their talking about.
a little knowledge is a dangerous thing!

Limited knowledge, ..... haha, you'll have to enlighten me then. lol!!

I've probably forgotten more than you presently seem to know!! The gap that you're talking about, only occurs during the event of an internal explosion, the width of the extended flat mating surfaces are designed to expand just enough to allow the controlled escape of safe cooled gases to the surrounding potentially hazardous atmosphere.

Anyway, so what is so different from what i've stated earlier on in this thread, to your new 4 pennies worth??

You're the guy enquiring about choc blocks and talking about 20KA fault currents aren't you? Are you using these choc blocks in Ex'd enclosures then and forgot to mention that little bit of info?? BTW, what method do you employ to IR circuits at your site??

 

[pepparz]

wow this is getting exciting.

who said ive been doing glands for 3 years? been installing and calibrating process equipment such as I/P convertors, pressure transmitters, massflow meters and other 4-20mA stuff im sure you can relate to that toonlad.

the post about connectors was me trying to find out at what fault currents if any are connector blocks designed to,but seems no one knows.

didnt seek out to knock eng54 but his post made me chuckle.

lots of love,looking forward to the next onslaught.

 

[pepparz]

ill just add this, the gap does not occur during a explosion its always there and it is measured with feeler gauges. just remember to use a silicon based grease to prevent the flamepath from rusting.

 

[pepparz]

nearly forgot,dont add chock blocks to flameproof enclosures as it an illegal modification

 

[shanky887614]

Lol nice to know it took you 3 yrs to make glands off.. speedy gonzalas, before you were unaided. lmao some achievement. Whahahahahahahahahahaha. Can you link up with specs and post some funnies, in the jokes section. Whahahahahahahaha

That proves nothing. It just means you could have been doing it badly for 13 years. Hell ive seen sparks that have been doing it for 25-30 years and they were terrible (qualified)


Ok mate what specific regulation are you talking about id like to know so i can look it up

 

[pepparz]

yep thats right ive been doing it badly for 13 years for the same chemical company checked by the same insurance inspector and the same instrument engineer,im surprised im still in emploment hahahahaha your pathetic attempts to discredit me will never work Whaahahahahahah *pulls black cloak over head and disappears in a cloud of smoke*

 

[shanky887614]

yep thats right ive been doing it badly for 13 years for the same chemical company checked by the same insurance inspector and the same instrument engineer,im surprised im still in emploment hahahahaha your pathetic attempts to discredit me will never work Whaahahahahahah *pulls black cloak over head and disappears in a cloud of smoke*

Im not having a dig just saying that experience isnt everything and just because someone has done something for a long time doesnt mean there good at it or know what they are doing

 

[shanky887614]

What reg number can i refer to about this?

Surely if you have been doing it for 13 years you would have mentioned this as they can't argue with the regs in front of them

 

[pepparz]

after having time to reflect on my posts ive decided to apologise to D Skelton, sorry mate it was wrong and unfair of me to mock and name call, hope you will accept this and think no ill of me.

 

[pepparz]

Im not having a dig just saying that experience isnt everything and just because someone has done something for a long time doesnt mean there good at it or know what they are doing

for god sake never knew i had to justify myself, this is a forum for offering advice not a site for proving yourself.

 

[shanky887614]

for god sake never knew i had to justify myself, this is a forum for offering advice not a site for proving yourself.

Not asking to prove yourself just the regs so can have a quick look to satisfy curiosity

 

[pepparz]

Not asking to prove yourself just the regs so can have a quick look to satisfy curiosity

curiosity about what?

are you talking about some other regulations than bs7671? if so which?

 

[pepparz]

if you need satisfying go see the wife:heart:

 

[pepparz]

Im not having a dig just saying that experience isnt everything and just because someone has done something for a long time doesnt mean there good at it or know what they are doing

now this does make me chuckle.ive got the qualifications but these are just bits of paper that anyone can get, the real proof in the pud is experience and having every single job inspected and passed by inspectors who have said they would be more than happy to give me recommendations but i dont have to justify myself, im earning a living and in 25 years have never been unemployed or sacked and had only 3 employers.

 

[Darkwood]

I feel this explosion risk is nothing compared to what American ex-secret files have shown ...regarding nuclear accidents where they were literally moments away from a nuclear bomb going off on home soil in poulated area..... i take it this aint the kind of explosion under discussion?

BBC News - US plane in 1961 'nuclear bomb near-miss'

 

[timbobelfast]

Peppaz, I think you have been exposed to too many IIC gases!

 

[pepparz]

Peppaz, I think you have been exposed to too many IIC gases!

hydrogen or acetylene?

 

[Knobhead]

I did my gas training at the Safety in Mines Research Facility. A fantastic place, explosions galore!

The test rig for testing motors is fun, they have a motor with an over large flame path. Quite spectacular when the surrounding atmosphere is at just below to upper explosive limit.

 

[pepparz]

Not asking to prove yourself just the regs so can have a quick look to satisfy curiosity

the reg is BS EN60079 series. does that satisfy you on this sunny saturday?

 

[pepparz]

I did my gas training at the Safety in Mines Research Facility. A fantastic place, explosions galore!

The test rig for testing motors is fun, they have a motor with an over large flame path. Quite spectacular when the surrounding atmosphere is at just below to upper explosive limit.

is that near area 51 in nevada?

 

[SPARTYKUS]

is that near area 51 in nevada?

I wouldn't know, I am actually a heavy goods train driver, I appear to have registered on the wrong forum. Damn this predictive text !

 

[pepparz]

I wouldn't know, I am actually a heavy goods train driver, I appear to have registered on the wrong forum. Damn this predictive text !

Hahaha nice one.

 

[D Skelton]

after having time to reflect on my posts ive decided to apologise to D Skelton, sorry mate it was wrong and unfair of me to mock and name call, hope you will accept this and think no ill of me.

Thank you, apology accepted.

 

[Engineer54]

ill just add this, the gap does not occur during a explosion its always there and it is measured with feeler gauges. just remember to use a silicon based grease to prevent the flamepath from rusting.

Well it is and it isn't...lol!! Machined flat faces without seals or gaskets will always have a gap. As far as i remember the limit on any such gap on flameproof flanges and the like is around a max 0.004'' depending on the type of gas/vapours involved. You measure any such gap in accordance with manufacturers recommendations to ensure that the gap does not exceed specification after the flange bolts have been correctly torqued down.

In the event of an internal explosion, the internal pressure created, will in it's own right expand any such gap, but still within the tolerances of it's type testing....


Things may have changed a little these days, as now i understand that Aluminium flanged enclosures are now often used in division 1 / Zone 1 - 0 and Ex 'd' equivalents. I've only ever used the heavy cast iron type enclosures!!

BTW, you didn't mention what method of IR testing you use at your site??

 

[Des 56]

The magic of air filled flameproof enclosures has now been revealed to the masses by pepparz in this thread
I am at a loss why he felt the need,some have worked in the mines most of their lives and didn't feel that urge
Was it something someone said?

and
Part 2 will now take the form of intrinsic safety and the use of the intrinsically safe Metrohm

Away to go then lad
This will be for the non explosive members benefit and general forum educational purposes perhaps

Next term oil filled switchgear as flameproof enclosures,a concise history

 

[Knobhead]

I'm dropping out of this before I blow a gasket!

Sorry a 0.005" FLP flange.

0.004" Min 0.006" max.

 

[Darkwood]

I remember when i had a customer where they filled gas bottles from nitrogen to oxygen thus the site was no Mobile Phones .... bring me in with a intrinsically safe mobile and see all the management start flapping because i answered my phone while working on a motor next to a oxygen filling tank.... they had never heard of a safe phone for use ...even got funny looks in tesco petrol station and when i said its intrinsically safe she said whats that mean .... told her and she went UH! i have to follow rules .... told her its a shame when your guidelines and your boss are so ill educated ....makes you wander exactly what they get payed for!

Went into have a chat with manager of local tesco's branch a week later and still they stuck to policy ... i left saying i thought you was a manager with discretion at your will.... seems you just another puppet not allowed to think for yourself.... he didn't like that at all ... i still get daggers when i see him lol .... hasn't stopped me using the phone though sometimes i do it on purpose cos im evil like that

 

[pepparz]

ah yes the oxymoron that is the intrinsically safe tester. i would personally IR in the conventionally way in the safe area,but if you need to do it in zones 2 or 1 on the kit make sure you do a gas test and have a hotwork permit.
pit electricians, ah the ones who when ty wrapping swa above ground still leave large drip loops between every ty.

 

[Engineer54]

ah yes the oxymoron that is the intrinsically safe tester. i would personally IR in the conventionally way in the safe area,but if you need to do it in zones 2 or 1 on the kit make sure you do a gas test and have a hotwork permit.
pit electricians, ah the ones who when ty wrapping swa above ground still leave large drip loops between every ty.

Actually this was a genuine question, seeing as you were/are working in a Hazardous Div 1 Zone 1
enviroment. The reason i asked, is that the old universal standard ''Intrinsically Safe'' Metrohm (that i still own) is no longer classified as intrinsically safe, and so no longer allowed on European EX 'd' sites. Soooo, i was wondering what has the Metrohm IR tester been replaced by, when needing to conduct IR tests in such hazardous areas??


I will hasten to add, that i still use my Metrohm intrinsically safe in such areas, as i have always done for the last 30 odd years, ...and with no detrimental effects whatsoever!! I also believe they are still sold by the present manufacturer for use within hazardous areas outside of the EU. That's Europe for you!! lol!!

 

[pepparz]

Actually this was a genuine question, seeing as you were/are working in a Hazardous Div 1 Zone 1
enviroment. The reason i asked, is that the old universal standard ''Intrinsically Safe'' Metrohm (that i still own) is no longer classified as intrinsically safe, and so no longer allowed on European EX 'd' sites. Soooo, i was wondering what has the Metrohm IR tester been replaced by, when needing to conduct IR tests in such hazardous areas??


I will hasten to add, that i still use my Metrohm intrinsically safe in such areas, as i have always done for the last 30 odd years, ...and with no detrimental effects whatsoever!! I also believe they are still sold by the present manufacturer for use within hazardous areas outside of the EU. That's Europe for you!! lol!!

no idea what theyve been replaced with. u can use what ever IR machine u want so long as u do a gas test to prove no flammable atmosphere exists. this is of course a continual gas test. but i just do it in the safe area and test the whole circuit with lids ON.very rarely have i had to IR in zoned area

 

[D Skelton]

Quite the little battle going on here, still, I think it could be more epic! Pepparz, for a bit of all out war why don't you ask Eng about 3/8" unthreaded earth rods, I know he loves talking about them!

 

[High Tower]

Quite the little battle going on here, still, I think it could be more epic! Pepparz, for a bit of all out war why don't you ask Eng about 3/8" unthreaded earth rods, I know he loves talking about them!

Don't u dare!!, you will be telling him to ask about exporting PME's next.................

For the love of god, do not poke the bear lol

 

[Clive P]

Hi,

Continuing on from E54's post ref the Intrinsically safe Metrohm; yes I still have mine too.
If I remember rightly this was deemed not suitable for use in the UK when the regs were updated due to the fact that it had to produce a test current of greater than 1mA ( if memory serves me right ) and we had to revert to the standard tester ensuring we carried out an atmosphere test before use. All of our resistance tests carried out with an Intrinsically safe Multimeter.
There was also something about dissipating stored energy, which I believe the Metrohm also catered for, ie, testing MICC where you needed to discharge the stored energy as the cable acts like a capacitor.
As E54 says , you can still buy this Instrument, but it is now called a Safety tester.

Regards.

 

[Engineer54]

Hi,

Continuing on from E54's post ref the Intrinsically safe Metrohm; yes I still have mine too.
If I remember rightly this was deemed not suitable for use in the UK when the regs were updated due to the fact that it had to produce a test current of greater than 1mA ( if memory serves me right ) and we had to revert to the standard tester ensuring we carried out an atmosphere test before use. All of our resistance tests carried out with an Intrinsically safe Multimeter.
There was also something about dissipating stored energy, which I believe the Metrohm also catered for, ie, testing MICC where you needed to discharge the stored energy as the cable acts like a capacitor.
As E54 says , you can still buy this Instrument, but it is now called a Safety tester.

Regards.

Had to have a chuckle about using standard IR testers in hazardous installations. There was a time when you would have been booted off the site and banned from ever returning if found using one!!

Outside of Europe, i've found the Metrohm is still the standard issue to maintenance electricians on such installation sites... Hard to believe a standard IR tester can be used in O Zones, as it is deemed to be a continuously hazardous zone, ...or used to be!! lol!!

 

[Des 56]

It says it all when practices that have stood the test of time are put aside for H+S drivel

 

[SPARTYKUS]

H+S drivel gone mad - an example - used to work on a huge site (Gas Board), had a bar on site n' everything, well it also had a heated outdoor pool.

back in the nineties I turned up one day with my cossie and popped down at lunch time to it, all gated up so went back to the jobsworth and asked "whats happened to the outdoor pool?"

"filled it in and slabbed over it"

me: "er, why?"

Jobsworth: "dangerous. Someone might drown"

I nearly passed out from the miasma of stupidity in the air

 

[Brightspark2]

H+S drivel gone mad - an example - used to work on a huge site (Gas Board), had a bar on site n' everything, well it also had a heated outdoor pool.

back in the nineties I turned up one day with my cossie and popped down at lunch time to it, all gated up so went back to the jobsworth and asked "whats happened to the outdoor pool?"

"filled it in and slabbed over it"

me: "er, why?"

Jobsworth: "dangerous. Someone might drown"

I nearly passed out from the miasma of stupidity in the air

Ha ha stood there in your flip flops, speedo's and towel...ha ha

Question is do you still own the Speedo's? Lol

 

[SPARTYKUS]

Ha ha stood there in your flip flops, speedo's and towel...ha ha

Question is do you still own the Speedo's? Lol

yeah but can only get one leg in them now