Ideal grounding point for ESD

[Sceadwian]

A broken water pipe cannot cause a short from live to ground. If there were the case, and it was a common occuranace, there would be alot of fried people. Using a cold water pipe for grounding is a very common practice, and nobody ever gets hurt by it.

I would beg to differ. This is a common case common enough there's code requirements, iron pipe coming into the house, copper pipe in the house. Do a straight metal on metal union and you have a galvanic cell that will cause the pipe to corrode at that junction to some eventual failure, pipe breaks water pours into the house causes an electric short circuit in a device in the basement that causes live to be connected directly to the houses ground which because the water pipe broke is now floating.

In the US this is easily solved by the simple code requirement that all dissimilar metal piping has to be joined with plastic fitting and separate clamps and a grounding strap have to be used to bond the two systems. If the pipe breaks the grounding strap will still allow GFCI's or breakers to trip before property fires or personal electrocution can occur.

 

[BrownOut]

Nobody is talking about flooding basements. We're talking about grounding to a cold water pipe for ESD protection. There remains no problem with using the cold water pipe for this purpose. Besides, I doubt the NEC even allows using the plumbing system for grounding.

NEC Compliant Ground Electrode Systems
The long-term integrity of the electrode/conductor connection is critical to ground electrode
system performance. The ground rod and the ground conductor bond is fundamental to a long
term, low resistance ground system. Selection of a proper system is mandated by UL 467 NEC
250, which requires careful coordination of components to avoid dissimilar metals and their
resulting galvanic corrosion problems.
Fifty plus years ago, UL defined a full 0.500", 10 mil copper bonded steel rod as the minimum non
ferrous clad ground electrode to bear the UL marking based on testing by the National Bureau of
Standards from 1910 -1955 that confirmed its long service conducted. The full 1/2" and the more
common 5/8" 10 mil 8 foot UL Listed copper ground rod have served the industry exceptionally
well, providing a 40+ year life, typically 4 times that of a ¾” galvanized ground rod.

 

[Sceadwian]

However, recently I have been becoming worried that I could be shocked if an item in my home is faulty. Therefore I have thought about the possibility of grounding myself to an independent rod outside my house. However, I wanted to write and ask if this is safe, or if there is an alternative way to ground oneself that is more ideal.

There are conditions a house can be placed under such as pipes freezing, corrosion breaks, accidental disconnections, and miswired/faulty equipment which are very real BrownOut, king.oslo was looking for suggestions for BETTER grounding methods. A dedicated grounding rod for the ESD discharge point removes the house from the ESD discharge system equation (so long as the grounding rod is sufficiently distant from the homes ground point).

 

[BrownOut]

The method I suggested is safe and commonly used without any danger. It's a great way to connect for grounding and used everyday without any injury. He can decide for himself which method to use, but he is totally safe using a cold water pipe. After all, people aren't commonly executed in the shower

 

[Sceadwian]

BrownOut, I never once anywhere said your method was unsafe, it's generally fine, the specific cases I've brought up however do exist and have happend, occurance level was never brought into the picture. The poster was searching for BETTER grounding methods, I'll highlight that one more time, and just leave it with a final comment as to not to take up anymore time trying to address a specific request of the original poster.

However, I wanted to write and ask if this is safe, or if there is an alternative way to ground oneself that is more ideal.

Grammer aside =) A separate dedicated ground for ESD protection will in fact protect from hazardous housing electrical problems better than simply tapping the houses existing ground.

Thankfully the possible dangerous non use of a resistor on the ground matt/strap were addressed, having a solid metal bench or a wrist strap with a low ohmic resistance to ground could be easily fatal.

One final thing I'd like to add is that outlet/wiring to which the ESD is grounded should be GFCI protected. If anything bypasses the resistor it prevents from fatal electrocution.

 

[Reloadron]

Gawd, I hate this stuff. Discounting grounding specific to ESD. Here is what the NEC (2008 Version and it is updated every 3 years, I have yet to see the 2011 version). The following is for your reading pleasure:

250.52 Grounding Electrodes.

(A) Electrodes Permitted For Grounding.

(1) Metal Underground Water Pipe. A metal underground water pipe in direct contact with the earth for 3.0 m (10ft) or more (including any metal well casing bonded to the pipe) and electrically continuous (or made electrically continuous by bonding around insulating joints or insulating pipe) to the points of connection of the grounding electrode conductor and the bonding conductors. Interior metal water piping located more than 1.52 m (5 fu) from the point of entrance to the building shall not be used as a part of the grounding electrode system or as a conductor to interconnect electrodes that are part of the grounding electrode system.

That is only the portion pertaining to Water Pipes. The ten feet pertains to the exit point from the building. Within the building you need to bond (they like that word) to the pipe within five feet of entry and there cannot be any couplings. If couplings exist they must be jumped with a minimum of AWG 4.

Grounding pipe or rod must be a minimum of 8 feet (***** when you keep hitting rocks) and a minimum 5/8" diameter. Also in lieu of a rod or pipe metal plates can be used with specifications for size.

The NEC actually takes this grounding stuff seriously.

In general article 250 deals with grounding but there are pages and pages of article 250. Also, in many cases in addition to the Grounding Electrode in many cases a single electrode is not adequate. I have for example an emergency natural gas powered generator. That requires its own Ground Rod in addition to the Water Pipe in the basement. I know damn well that pipe exceeds 10 feet as I buried that *******.

Again, nothing to do with ESD but that is a small part of what the NEC says.

Ron

 

[BrownOut]

MOD EDIT: Please keep on topic and productive

 

[Sceadwian]

MOD EDIT: Please keep on topic and productive

 

[BrownOut]

MOD EDIT: Please keep on topic and productive

 

[Reloadron]

Yeah, there are volumes of ANSI text written on this crap. The thing is we have a member with a home situation, it's not like some critical thing. Ground it and that's that. I agree and the questions were more than adequately answered. Hell, it was interesting.

Ron

 

[king.oslo]

Thank you for your time. I have become much wiser in regards to grounding!

Kind regards,
Marius

 

[king.oslo]

Hello,

I would like to check if the cold water pipe has good grounding.

I figured that one way of testing it would be to insert a probe into the mains, and one probe on the pipe and read the voltage across.

I am afraid of plugging a probe into the mains, and wanted to ask if there is another way to do it?

Thanks.M

 

[Reloadron]

Grounding for ESD? I believe we covered that and a cold water pipe assuming it is earth buried at some point would be fine with a copper pipe preferred.

Rom

 

[king.oslo]

I live in a building where it isn't easy to visually inspect whether the cold water pipe is grounded. So I would like to test it somehow.M

 

[Reloadron]

Then I would consider what you mentioned:

I figured that one way of testing it would be to insert a probe into the mains, and one probe on the pipe and read the voltage across.

Personally I have no problem working with mains power, including 480 volt three phase mains and much higher. I am comfortable with it so it really doesn't bother me. Measuring between mains high (hot) and a water pipe should display mains voltage. Then too, I have no clue as to Norway power distribution. The method you mentioned should work fine, obviously observe caution.

Ron