Residential 600 Amp Gas & Water Bonding requirement

[kwired]

Thank you for clearing that up for me. I thought it was based upon available amps running inside the home. But it’s available amps running to the home.

Load calcs came in at 570 amps so essentially 600....

Idk if the water service is metal pipe underground between the shutoff and the meter. I’ve seen them use pex for this before. I’m pretty certain the plumber ran 1” rolled copper between the main house and the pool house (50ft) does this qualify GEC at that shut off? Sounds like it may, pool house is a 125amp sub off one of the 200s

So the gas I assume is considered metal throughout despite it not being typical cast iron, they ran a flexible trunk line that wasn’t the typical yellow it was black....


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Minimum GEC is sized per ungrounded service conductor size, regardless of load calculation or overcurrent protection. Just because you "essentially have" 600 amps doesn't mean you can't have 800 amps worth of conductor because someone decided to increase because of voltage drop - which makes that 600 figure irrelevant when sizing the GEC.

If you can't determine whether the incoming water is metallic or not, I'd at very least connect to the known copper line - it still is a qualifying electrode. If main line is metallic as it exits the building the chances are pretty good it is a qualifying electrode also, how often do they replace an old line with non metallic but connect to existing within 10 feet of entry? If it runs below floor before entering maybe, if it enters a basement wall, they pretty much always replace the entire line to and usually including the first shutoff valve.

 

[kwired]

Can you expand on this a little?

Suppose I have a small house with gas. The calculated load is no more than 100 amps. I install a 200 amp main/service panel. What size service entrance conductors are required?

General rules state you must have conductor sized at least enough to handle calculated load, and minimum overcurrent also accordingly. Then there are some rules that give minimums for certain applications and that will be 100 for a single family dwelling.

If you decide to go with a single 200 amp service disconnecting means then you must use 200 amp service conductor or at least apply next size up rules where applicable. If you are using permitted 2-6 service disconnecting means your common supply conductors only need be sized per the load calculation. You could have 3 - 200 amp mains but a load calculation of 425 amps - in that case NEC only requires minimum conductor ampacity of 425. Some may choose to use 600 amp but do not have to. If you had same load but a single 600 amp main then you must use 600 amp supply conductors (or at least apply next size up rule if conductor falls between 500 and 600)