NFPA 70E 90.2(A) and (B) and CSA Z46s define which installations are covered by the respective standard and which are not.

For our friends outside the U.S. and Canada, perhaps you use NFPA 70E even though it is a U.S. standard. We would love the hear about it!

For the majority of your company's / clients facilities, does NFPA 70E or CSA Z462 apply?

• Yes
• No
• No - but we use it anyway

MSHA doesn't even follow NEC except some sections of NEC-1976! We follow it anyways in MSHA areas as a guidance standard, along with 70E. Our overhead distribution group is following NESC, which is significantly different from 70E. The corporate guidance document is dual-nationality (70E and CSA Z462)...fortunately that is pretty easy to maintain since 70E and Z462 are virtually identical except the annexes.

I'm based in Europe, where arc flash hazard studies are entirely optional and only performed by a select few industries (some in oil and gas, but in the UK the marine society is surprisingly ahead of the curve). The other source of interest is US based companies wanting a uniform electrical safety program worldwide, taking their own minimum requirements as a starting point.

My experience is that it begins with an effort to just use NFPA 70E down to details like shock hazard boundaries, which is a bad idea. NFPA 70E and it's European equivalent EN 50110 are pretty similar in intention for shock hazard, but it breaks down from there. However, the EN 50110 doesn't even mention arc flash hazard and this is where NFPA 70E can really be helpful in setting additional requirements. Some of the references do not always apply (ASTM test standards for example), but those can often be replaced with European equivalents.

The easiest way to get started is to let individual sites use their local regulations - which will be based on EN 50110 - for shock hazard protection and add arc flash hazard policy on top of that, using NFPA 70E for inspiration. Additional safety requirements are never a problem and fits neatly into the spirit of EEC regulations.

Article 90.2 (B)(2) excludes surface and underground mines.

It is not that simple. NEC article 250.188 provides specifics for mobile equipment grounding, such as surface mining equipment. For example, neutral grounding resistors must be used, along with neutral ground resistor checking systems. And article 400 part III for cable and article 490.51 apply to surface mining equipment.

Despite the exclusion in the code books, both the NEC and 70E are used in USA surface mining. If there are deviations, they are minor and well considered.

I heard that CSA pretty much uses NFPA 70E verbatim while paying royalties and "Canadianizing" it. Other than the annexes, are there any other differences?

It is not that simple either. Yes, NEC at least appears to exclude surface mobile mining equipment and all underground equipment, despite having sections like article 250.188 that would specifically apply to mobile mining equipment. Technically NEC does apply to for instance a non-portable pumping station.

Despite the way it is written, mines do NOT follow any part of OSHA (29 CFR), and although some states (New Jersey, West Virginia are two I am absolutely certain about) have jurisdictional authority, in many states they are excluded from enforcement either partially or completely. NEC is required at the state level, not federally. In states where states do enforce mining laws, I haven't seen a case in surface metal/nonmetal where they have enforced the parts of NEC you quoted. All mines fall under MSHA (30 CFR). There are regular turf battles back and forth between the two agencies. To make it even more confusing, surface metal/nonmetal is treated differently from the others (coal both surface and underground, and underground metal/nonmetal). In the coal/underground mines, MSHA has their very own version of "UL" and certain equipment must be MSHA approved (CE and UL are not sufficient).

MSHA treats NEC as part of that "OSHA stuff" and doesn't enforce except when it is convenient for them to do so. Basically almost all mining regulations are subject to the whims and vagaries of the MSHA inspectors. Their own regulation is incredibly poorly written and routinely gets them tied up in law suits. There is currently a court backlog of 6-8 years. MSHA inspectors pretty much ignore federal court rulings as well, and there are some famous cases where this has happened. In one case, the courts ruled against MSHA and on the very NEXT visit, the MSHA inspector cited the prevailing company again for the exact same reason, saying essentially "go ahead and sue us". The situation has gotten even worse since MSHA now recognizes enforcement actions as a profit center for their agency and has stated this pretty openly.

High resistance grounding and ground check systems are only required in coal and underground operations. They are not required in surface metal/nonmetal mines, and the vast majority of them either don't use either or use only the high resistance grounding part. This is well settled. It irritates the coal miners to no end that those "gold and sand mines" are exempt and they will be pretty up front about this. It's not so much the high resistance grounding as it is the ground check system that is a royal pain on surface and has a lot of practical as well as theoretical weaknesses.

Where the sections of NEC that you mentioned ARE required would be for instance ship unloaders that are very similar to a mobile coal reclaimer/stacker in design.