Grounding
Grounding
(OP)
I'm in doubt about grounding instruments. I have EExd instruments and IS (intrinsically Safe) Instruments. I saw a long time ago one project showing 2 grounding bars, one for EExd instruments and another one for IS instruments. Should IS instruments grounded in a separated bar? Is there one standard saying this?
Sorry for my poor English!!!
Best regards
Sorry for my poor English!!!
Best regards





RE: Grounding
Roy
RE: Grounding
"a grounding system that has a dedicated conductor isolated from the power system, except at one point, so that ground currents will not normally flow, and that is reliably connected to a grounding electrode in accordance with Article 250 of the NEC ®."
RE: Grounding
Johnny H-S BSc(Hons) MInstMC
Engineers like to solve problems. If there are no problems handily available, they will create their own problems.
RE: Grounding
Well, that's only really true of Ex 'D' isn't it? All the others rely on preventing the explosion occuring: 'E' and 'N' basically pray to God that nothing involving sparks will happen in among their cheap and flimsy innards otherwise it's Game Over, and most of the others ('M', 'O', 'P', 'Q') use some means or other of preventing the explosion happening by preventing the spark coming in to contact with the fuel-air mix.
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If we learn from our mistakes I'm getting a great education!
RE: Grounding
This is a good link for explanations for those i have confused!
http://www.gfienterprises.co.uk/Atex.html
Johnny H-S BSc(Hons) MInstMC
Engineers like to solve problems. If there are no problems handily available, they will create their own problems.
RE: Grounding
Johnny HS reply has already give the answers. Ijust want to add a bit more.
Typically, all electrical equipments shall be gorunded on the dirty earth and all instrument shall be ground at clean earth.
But if we have mix of Flameproof (EEx d) and IS (EEx i) instrument, we need two clean earth (even saperate cables), one for EEx d instrument and another one for IS instrument. Tppically, the IS clean earth shall be at the IS barrier.
Main thing is:
Flameproof = Explosion shall contian inside the secured area
IS = current limiting. By doing this, spark cannot accours.
RE: Grounding
One of those IEEE color books covers grounding details too.