Because of this arrangement, doesn't the home(s) service take the brunt of any fault caused by the utility ?Right because the messenger is the grounded/neutral conductor. Perhaps I'm not understanding what you are asking?
Can you be more specific about this fault? It's hard for me to imagine a scenario where any significant primary fault current would be traveling into the building. My biggest concern would be an Open primary neutral which may elevate the potential of the grounded conductor in the building, that is why I would prefer they do not make the primary to secondary neutral connection.
How about a lightning strike on the utility line ?
To which conductor? If it it's the phase conductor I see it the same either way. If it hits the utility neutral then I suppose on paper it has a direct path into the building because of the primary to secondary neutral connection. However there may not be any increase overall risk as there are other things that play, like the low resistance of the utility primary to Earth, the fact that lightning doesn't travel very far on conductors, etc. I think there is an argument to be made that MGM systems are better at dealing with lightning events. Are you aware of any statistics that show otherwise? I think I'm going to have to ask for evidence before just accepting a claim that lightning damage is more prevalent on MGM systems with a primary to secondary neutral tie.
I do appreciate your detail responses you have made and the understanding that we both agree on how services should be connected to the utility. And how expensive it would be to provide a separate transformer for every service to make it safer.
My preference is this: I don't really care about the MGN, but I would like the secondary neutral to be isolated from the primary neutral. I would also like an underground water pipe to be prohibited from being used as an GE and a dielectric union used .
I agree 100% ... Last year I replaced my old, galvanized pipe water service with copper and a dielectric union.
If both the secondary and primary neutral are earthed (grounded), then they will be at (approximately) the same potential. What is the advantage of having them only connected through earth, rather than solidly bonded together?
If you decide to eliminate the grounded connection between the primary and secondary on the transformer. Don't forget to remove the uninsulated neutral wire from the messenger wire service drop and provide an insulated neutral to the service drop.
They install a rod or a pole butt electrode at every pole that has a transformer and no more than 1200' apart along the pole line.
I have attached a picture of my Electrical Service for clarification.
The potential issue I see with primary and secondary neutrals solidly bonded is the secondary neutral could see a rise in potential with a utility open neutral. You can come up with scenarios where this connection would be beneficial however.
I dont follow what you are saying here. Would you mind trying again with more specificity?
I think a good place to start would be to look at the use of the water service bonding requirement in the NEC. When I upgraded my water service, I installed dielectric union, but still kept the bond to the interior water piping. So, let's talk about that for starters.
