Corrosive Environment/N4X

L

Lemay

Member
Location
South Florida
Occupation
EC
Recently, during a review cycle in Miami Beach for a Service Replacement, the Authority Having Jurisdiction (AHJ) required the owner to sign a Hold Harmless Agreement because the Group Metering Equipment was rated NEMA 3R instead of NEMA 4X. The AHJ referenced a Memorandum that broadly classifies all coastal areas as corrosive environments. Based on the research I’ve gathered, this interpretation appears to be an overreach of the applicable standards.

Next week, I’ll be presenting this case at the BORA hearing for clarification.

From my review of multiple regulatory standards, corrosive is consistently defined as a reaction involving living tissue, not environmental conditions or exposure to salt air. Furthermore, the Group Metering Equipment we are installing is not manufactured in NEMA 4X due to its "Hosedown" rating, which makes sense—nobody would take a garden hose to unfused electrical equipment.

I’m seeking input or advice from anyone with relevant experience or insights that could strengthen my case. Here are the references that highlight how corrosive agents and environments are defined in various standards:

References:​

  1. OSHA – Corrosive Agents (29 CFR 1910.1200):
    A corrosive agent is defined as a chemical that causes visible destruction or irreversible changes to living tissue at the point of contact.
  2. Florida Building Code (FBC) – [F] CORROSIVE:
    A chemical that causes visible destruction of or irreversible alterations in living tissue by chemical action at the point of contact. A chemical shall be considered corrosive if, when tested on the intact skin of albino rabbits per DOTn 49 CFR, Part 173.137, it irreversibly alters tissue within 4 hours. This definition explicitly excludes action on inanimate surfaces.
  3. U.S. Department of Transportation (49 CFR 173.137):
    Corrosive locations are defined by the chemical impact on living tissue, not general environmental conditions.
  4. National Electrical Code (NEC 2020, Article 680.2):
    Defines corrosive environments specifically in swimming pool areas and chemical storage locations where chemicals are stored, handled, or dispensed.
 
Lemay said:
Recently, during a review cycle in Miami Beach for a Service Replacement, the Authority Having Jurisdiction (AHJ) required the owner to sign a Hold Harmless Agreement because the Group Metering Equipment was rated NEMA 3R instead of NEMA 4X. The AHJ referenced a Memorandum that broadly classifies all coastal areas as corrosive environments. Based on the research I’ve gathered, this interpretation appears to be an overreach of the applicable standards.

Next week, I’ll be presenting this case at the BORA hearing for clarification.

From my review of multiple regulatory standards, corrosive is consistently defined as a reaction involving living tissue, not environmental conditions or exposure to salt air. Furthermore, the Group Metering Equipment we are installing is not manufactured in NEMA 4X due to its "Hosedown" rating, which makes sense—nobody would take a garden hose to unfused electrical equipment.

I’m seeking input or advice from anyone with relevant experience or insights that could strengthen my case. Here are the references that highlight how corrosive agents and environments are defined in various standards:

References:​

  1. OSHA – Corrosive Agents (29 CFR 1910.1200):
    A corrosive agent is defined as a chemical that causes visible destruction or irreversible changes to living tissue at the point of contact.
  2. Florida Building Code (FBC) – [F] CORROSIVE:
    A chemical that causes visible destruction of or irreversible alterations in living tissue by chemical action at the point of contact. A chemical shall be considered corrosive if, when tested on the intact skin of albino rabbits per DOTn 49 CFR, Part 173.137, it irreversibly alters tissue within 4 hours. This definition explicitly excludes action on inanimate surfaces.
  3. U.S. Department of Transportation (49 CFR 173.137):
    Corrosive locations are defined by the chemical impact on living tissue, not general environmental conditions.
  4. National Electrical Code (NEC 2020, Article 680.2):
    Defines corrosive environments specifically in swimming pool areas and chemical storage locations where chemicals are stored, handled, or dispensed.
Click to expand...
The NEC rule in 680 has nothing to do with living material. It is only related the the corrosion of the electrical equipment.
Sure there are chemicals that also "corrode" human flesh, and that definition makes sense in an OSHA document to protect people.
This FEMA document applies corrosion to structural metal parts in salt areas. There was a recent discussion as to the application of this information to electrical equipment on another site, but no real conclusion was reached.
 
Don: Good evening, I appreciate your feedback.

I'm wondering then why thee regulators haven't explicitly classified Coastal areas as Corrosive Environments. If you have information from any regulatory standard giving that information then please share.

Additionally, as for the FEMA document I don't disagree, however, I don't see the correlation between a $10 metal beam strap and a Utility Enclosure.

I'm not arguing the accelerated deterioration of metal enclosures in Coastal areas, I'm more concerned with the fact that the City is requiring the use of a non-existent piece of equipment for compliance.

All the same, appreciative of the feedback.
 
Ask if a stainless 3R would work.
I worked some of the coastal rebuilds, nice beach houses few hundred feet from the beach, my boss at the time was going nuts looking for a 4X fibreglass or non metallic meter base all we found was a stainless in a 3R.
The EC doing the house next door got away using a regular 3R meter pan.
That was ~12 years ago and when I was out there in December that stainless meter base looks fine and the meter on the house next door is totally rusted out LOL.
 
Lemay said:
Don: Good evening, I appreciate your feedback.

I'm wondering then why thee regulators haven't explicitly classified Coastal areas as Corrosive Environments. If you have information from any regulatory standard giving that information then please share.

Additionally, as for the FEMA document I don't disagree, however, I don't see the correlation between a $10 metal beam strap and a Utility Enclosure.

I'm not arguing the accelerated deterioration of metal enclosures in Coastal areas, I'm more concerned with the fact that the City is requiring the use of a non-existent piece of equipment for compliance.

All the same, appreciative of the feedback.
Click to expand...
I agree that the FEMA document does not address electrical systems, but like structural fasteners they are made of metal that can corrode.

The city really should have an amendment to the code if they want that, however they can accomplish that using 110.2.
 
gene6 said:
Ask if a stainless 3R would work.
I worked some of the coastal rebuilds, nice beach houses few hundred feet from the beach, my boss at the time was going nuts looking for a 4X fibreglass or non metallic meter base all we found was a stainless in a 3R.
The EC doing the house next door got away using a regular 3R meter pan.
That was ~12 years ago and when I was out there in December that stainless meter base looks fine and the meter on the house next door is totally rusted out LOL.
Click to expand...
IMO stainless 3R would only protect the enclosure itself from deterioration but not necessarily prevent deterioration of what is contained within.
 
Type 4x typically won't do as much to protect what is inside an enclosure as you might think.

It is water resistant but not air proof. Air moves thru the gaskets and the conduit.

Much better than type 3 though.
 
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