Environmental Potentials whole house surge protection, can I get your opinions?

NFPA is a human protection code; insufficient for transistor protection. Transistor protection both *meets* and *exceeds* those human safety requirements.

Human safety discusses resistance. Transistor safety also addresses impedance and equipotential. NFPA does not discuss the latter two. Because NFPA is only about human protection.

First you need to start with what is the intention of the National Electrical Code.

I did. Stated repeatedly in multiple posts. Appliances protection both *meets* and *exceeds* what is required by human protection codes such as NFPA.

IEEE defines how to exceed those codes. IEEE say why ’whole house’ protection is 99.5% to 99.9% effective. Plug-in protectors have no earth ground - maybe add another 0.2% protection. None of that contradicts what is good earthing for human protection and remains insufficient for appliance protection.

More quotes from various IEEE sources:

It is important to ensure that low-impedance grounding and bonding connections exist among the telephone and data equipment, the ac power system’s electrical safety-grounding system, and the building grounding electrode system. ..Failure to observe any part of this grounding requirement may result in hazardous potential being developed between the telephone (data) equipment and other grounded items that personnel may be near or might simultaneously contact.

Low impedance - not low resistance.

Martzloff’s 1994 IEEE paper says same about impedance because a protector (SPD) is only as effective as its earth ground:

An effective, low-impedance ground path is critical for the successful operation of an SPD. ... Therefore, an evaluation of the service entrance grounding system at the time of the SPD installation is very important.

An IEEE guide shows a protector, connected to a wall receptacle safety ground, earthing an 8000 volt surge destructively through a nearby TV. That protector was not connected low impedance to earth ground; was too close to and therefore damaged a nearby appliance. Again, protection defined by impedance - a short connection to earth. Protection not provided by a wall receptacle safety ground - that has low resistance and high impedance.

That same guide defines earthing that must exceed NFPA requirements:

To achieve optimum overvoltage protection, the connecting leads between the SPDs and the panel or protected equipment should be as short as possible and without sharp 90-degree bends.

90 degree bends and long wires (ie more than 10 feet) increase impedance (but not resistance). Therefore reduce appliance protection. NEC defines human protection; not appliance protection. Unfortunately electricians, who are taught code, are not taught concepts such as counterpoise, equipotential, and impedance. Concept necessary to upgrade earthing for surge protection.

Low impedance connection to single point earth ground is why the Cutler-Hammer and Leviton ’whole house’ protectors are so effective. With numbers (ie 50,000 amps) that define protection from direct lightning strikes. Because a protector is only as effective as its earth ground - including a low impedance connection.

Also critical is inspecting the ’primary’ surge protection layer - that is ignored by NFPA and NEC.

westom,

What is the purpose of the National Electrical Code?

The purpose of the National Electrical Code is the practical safeguarding of persons and property from hazards arising from the use of electricity.

Not your opinion or your interpretation of what you think it means. What does the sentence actually say?

Do NEC codes protect property from *all* hazards - as you have only assumed? Of course not. Codes only protect property from hazards that also threaten human life - such as fire. Appliances can be completely destroyed by other anomalies. NEC says nothing about protecting from those other anomalies. Destroyed appliances that do not threaten human life (ie that do not created a house fire) are ignored by the NEC.

Rather than argue philosophical and broad spectrum concepts, instead learn relevant electrical concepts. OP’s question is clearly about protecting household appliances from surges. Electrical concepts (ignored by NFPA and NEC) such as impedance, counterpoise, equipotenial, and where hundreds of thousands of joules are absorbed - these concepts you also repeatedly ignore. These concepts define protection. Nothing in the NEC discusses these concepts. Because NEC is totally about human protection.

Most critical item for appliance protection is single point earth ground. Earthing that must both **meet** and must **exceed** code requirements. Even measuring earth resistance (to meet human safety requirements) is insufficient.

Protection is always - as in always - about where hundreds of thousands of joules are harmlessly absorbed. A protector is only as effective as its low impedance (ie less than 10 foot) connection to and quality of earth ground. NEC does not discuss any of this: what is essential to protect all household appliances.

Better is to answer the OP’s question by learning well proven concept that you never heard before. Better is to ask questions about how to make earthing exceed what code requires - rather than argue the irrelevant. Defined is how protection was done successfully well over 100 years ago. Better earthing for appliance protection is an ’art’ - that you apparently refuse to learn because the NEC does not discuss it.

westom,

LOL,

You just ramble on and on saying the same things over and over.

As for my posts on this thread I believe I answered all the OP’s questions and concerns accurately. Starting with SPDs and the importance of the integrity of the electrical service’s grounding electrode system/earth connection.

I would ask you to go back to the start of this thread and read my posts, but I know it would be a waste of time. It is obvious you have a problem understanding what you read.

Your understanding of NEC leaves a lot to the imagination.

I know you won’t, but you should at least take the time and read Article 90 of the NEC. It might help you better understand the rest of the book.

Pay close attention to the highlighted last sentence of 90.1 (A)

This Code is not intended as a design specification or an instruction manual for untrained persons.

Then read 90.1(B)

(B) Adequacy. This Code contains provisions that are considered necessary for safety. Compliance therewith and proper maintenance results in an installation that is essentially free from hazard but not necessary efficient, convenient, or adequate for good service or future expansion of electrical use.

Then read the Informational Note just below (B).
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Through out this thread I said the NEC was bare minimum! I repeatedly spoke of the importance of the electrical service grounding electrode system/earth connection. I used IEEE recommendations, not NEC, for the minimum 5 ohm or less grounding electrode to earth resistance. I even said 2 ohms or less was better yet.
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