is my house properly grounded?

Old 01-16-18, 05:06 PM
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is my house properly grounded?

I noticed in the book, "wiring simplified" , based on the 2017 NEC, my house's breaker panel should be grounded to the cold water pipe and 2 ground rods driven into the earth.
I have an old house. Last time a real electrician worked on it was around 1965.
My breaker panel is not grounded with a wire to the cold water pipe or an in ground rod.
There is an in ground rod next to the meter. A wire runs from the meter to the ground rod.
I assume, my only ground is from the metal conduit that runs from the meter to the breaker panel.
My question is, is this considered properly grounded, or should i put in another ground rod and run three seperate ground wires from the panel to the cold water pipe, exsisting ground rod and new ground rod?
In other words, if it was your house, what would you do?
Old 01-16-18, 05:16 PM
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Do you have a metal water service coming into the house ?
Is it just the electric meter outside or is there a service disconnect too ?

Back in those days it was typical to connect a mini armored BX cable to the water service and not use ground rods.
Old 01-16-18, 06:18 PM
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The GEC is allowed to connect to the meter or even the weatherhead per NEC so that part is OK. Lots of POCOs don't allow it anymore even though some used to require it.
That said, if you have a water pipe coming into the house even in 1965 it was required to be used/connected to the GEC
Old 01-16-18, 09:10 PM
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Metal water service would depend on the definition of metal water service.
I have a metal pipe entering the basement from a well. Drilled well, casing head is exposed. Pump is in the basement.
No exterior disconnect.
Just the meter.
Story i was told was, in 1965 an addition was put on the house. The electrician required the 1930's style multible fuse boxes , meter in basement, no weatherhead , to be upgraded to a modern one breaker panel, meter outside with a weatherhead.
It might have been grounded to the water pipe at that time and some clown removed it, at some point in history.
It is an unfiished basement. Hand dug. Stone foundation. Ballon construction. There is no place to hide a ground wire. If there was one running to the water pipe, i would see it.
So, are you saying all i should do is run a ground wire from the breaker panel, to the water pipe from the well, and connect it with a ground clamp?
Old 01-17-18, 07:35 AM
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If the metal pipe is at least 10 feet long outside the foundation, you can use it as your grounding electrode via the method you describe. If the well casing is steel, you could use that for a very good grounding electrode. Otherwise, you'll have to add two ground rods, spaced 6 feet apart outside near the meter and bond those back to the electrical panel using acorn clamps and #6 copper wire.
Old 01-17-18, 08:23 AM
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One water pipe grounding electrode is required unless the pipe is known to not be metal running underground for at least 10 feet after exiting the house. Typically it is connected to the panel neutral bus (panel on or in the house and having the first master disconnect for the house) with a #4 copper wire (I don't have the wire size table handy now). The clamp on must be within 5' of where the pipe exits the house, with no water meter or other device in between.

The water pipe requirement is not relaxed because the qualifying pipe is at the far corner of the house from the panel.

Should the ground wire (grounding electrode conductor) from the second ground rod first reach the GEC for the water pipe or the GEC for the first ground rod, it may be clamped on there instead of go all the way to the panel.

Last edited by AllanJ; 01-17-18 at 08:40 AM.
Old 01-17-18, 08:31 AM
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Put the clamp on the water pipe right where it enters the house. Definitely before the check valve, if you have one. The point of this is so that when you go to replace the pump or check valve, you don't disturb that ground connection when you take stuff apart. Or you could get a nasty surprise.
Old 01-18-18, 06:05 PM
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i just measured it.
wellhead is 12 feet from the house, so i am within the 10' rule.
there is something, i am afraid to touch it, wrapped around the pipe for the first few inches, but then i have several feet of pipe before a check valve or even a joint. so, i can attach the clamp within a foot of where it enters the basement.
it is a 3/4" galvanized pipe.
i assume i have to wire brush the loose galvanized stuff off where i am going to attach the ground.

ground wire size.
wring simplified mentions the ground wire size depends on the size of the wires coming in from the meter. how can i tell what size those wires are? not like i am gong to wrap a tape measure around one.
one of my circuits is #6 wire and the wires from the meter look to be about twice the size of the #6.
length of ground wire will be 15'.

about 5' of the ground wire will run down a stone foundation. mortar is between the stones. does this wire have to be secured to the stone? or will a staple to a floor joist before it runs down the wall, be enough? if not, how do you secure a wire to stone? really dont want to penetrate the stone or mortar in any way. god only knows what will happen.
Old 01-18-18, 08:10 PM
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Number 6 copper is the correct size for a grounding conductor. Use an approved grounding clamp (not a hose clamp) on the pipe. Yes, it is a good idea to wire brush the pipe before adding the clamp although it is not absolutely necessary due to the teeth on the clamp will make a decent connection. The clamp needs to be within five feet of the point where the pipe enters the house.

Mod Note: #6 is all that is needed to a rod. The conductor to a waterline is based on the service ampacity. #4 CU is typical for a 200 amp service.

Last edited by pcboss; 01-21-18 at 01:10 PM.
Old 01-21-18, 11:30 AM
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ground wire size.
wring simplified mentions the ground wire size depends on the size of the wires coming in from the meter.

Typically a 200 amp service (2/0 or 3/0 copper OR 4/0 or 250 Aluminum Service Entrance conductor) needs a #4 copper or #2 aluminum GEC to the metallic water service and a 100 amp service (#2 copper or smaller OR #1/0 aluminum or smaller Service Entrance conductor) needs a #8 copper or #6 aluminum GEC to the metallic water service. I would use #6 copper to a ground rod for either a 200 or 100 amp service.

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