grounding and bonding

Assurance code, rule or

Its a huge issue in a chem plant... you need a book solely on the bonding issues. Builders Book Store will have one...they have outlets in most states... calif for sure...you can call SF Calif Builders Book Store and they can tell you what they have..it will cost you 100 dollars or so most likely.

My view on the issue just for starters, Corrosion at the copper ground wire to grounding rod needs to be prevented with a paintable rubber covering etc..and a heavy rubber wrap..some extreme measures... have a least for deep grounds one at each corner of the building...maybe a lot more.. insulate the grounds us thwn or better thoughout. Your grounds at switch and recepticle boxes will corrode to nothing if you use metal, so use plastic and run insulated copper grounds...

Many areas will have to be intrinsically safe... you need another book on that. It goes beyond bonds. You need to fresh air supply all of your breaker cabinets most likely even if the are not NEMA 4 required, you still need keep outside air blowing through then..

Outside air is a huge issue as its often contaminated and go to the explosive limits in accident scenario's...depending on the nature of the facilty, the purge air needs to be run though a hydro carbon/ acid absorber bed..

there is a lot to research here... you are designing NOT to meet NEC but to meet worst case accident scenario's. thats demanded by their prime insurance carrier in most cases.

In some areas you will have NEMA 4 or better enclosures in others just air purged NEMA 1 or 2.

If the job is going in from the slab up Id bury a heavy THWNN ground loop, twice as large as required by NEC..with taps to it wrapped in rubber tape coming up the side wall of the plant every 20 or 50' depending. (when the cement floor cracks chemicals will get onto your burried neutral)...then grounding to the rebar from this loop and to at least 4 separate ground rods..depending on soil conditions.

Thats about 5% of what you need to know in most risky situations...so you need the books for sure in this case...unless its some benign chemicals being made.. But petro chem, acids, and the like are a very risky proposition.. if Silane is involved you need to research that separately.

And understand that most of the existing plant people and even most EE's that dont have extensive industrial experience... will think you are nutz... these have no clue..thats another reason you need the books..just do your design then reference each detail on the drawings to these books (dont make a big issue of it)...and then dont argue with these folks... tell em when they say 'whats this'... go ahead and delete it, item 9 is addressed in chapter 14 page 292... that makes it very hard on those who think its not an issue...because 'the last plant hasn't blown up yet'.

Your added precautions might cost the client 1,000 dollars, the worlds cheapest insurance against 40 million in losses, and lawsuits.

I also design for 50 years down the road in these cases... my question is 'how will this be working down the road'..that also changes things a lot. I ask the clients how long the facility is planned to be there...in electronics its a year or two... those get a different approach than a petrochem plant that is planned to be an asset decades into the future.

Phil Scott

Where I live this program would be handled by the electrical engineer of record. The engineer would work at the plant or he would be under long term contract with it. The engineer and the local authority having jurisdiction would work out the installation, verification and periodic testing of the grounding systems. The inspections would be handled by the code authority and records of the testing would be kept on side by the risk management department. ( or who ever handles those things )

You might try Soars Book on Grounding for some reading.

The section of the NEC your quoting has absolutely nothing to do with a chemical plant. There could be Class 1 Division 1 explosion proof areas and even impractically safe areas. Each area of the plant will have to be classed and handled according to that class.

Do you have a risk management department? They should have a clue as to where to start. My experience has shown that dealing internally first is much better than going outside.

Last resort check with the insurance/bonding company, of record, for their requirements. It is to their benefit that they help you.