ECN Forum
Posted By: George Little Alarm Panel Grounding - 03/20/06 08:28 PM
When the instructions with the "Household Fire Alarm" panel tell the installer to ground the equipment by connecting ro a water pipe, is it acceptable to go to the nearest water pipe or would he need to go to within 5 feet of where the water pipe enters the building? Assume 10 feet of water pipe in contact with earth. Code reference please.
Posted By: gfretwell Re: Alarm Panel Grounding - 03/20/06 10:29 PM
George this looks like an issue you should take up with U/L or the other listing agency.
It is clear the writer of those instructions never saw plastic water pipe.
As an inspector I would want to see it bonded to the EGC of the circuit feeding it.
As an installer I would bond it to the PVC pipe with weedeater line and a tywrap for a clamp. (after I made the EGC connection in a proper manner)
Inspectors need a laugh too.
Posted By: HotLine1 Re: Alarm Panel Grounding - 03/20/06 10:31 PM
George:
FA/BA panels (majority) have a terminal for "earth ground". I never thought about 'where' till I saw your post. We accept a water pipe ground; basically at an accessable location.

Now, you have me thinking.......I'll crack the book after dinner.

John
Posted By: gfretwell Re: Alarm Panel Grounding - 03/21/06 01:50 AM
If I read that as a required connection, beyond a normal EGC, I would be thinking isolated grounding conductor.
Posted By: George Little Re: Alarm Panel Grounding - 03/21/06 12:45 PM
I'm still waiting for input and I know you guy/girls have an opinion, after all this is a grounding issue. I wrote a violation and didn't quote a solid code reference (bad move) and now I need some input. My violation said "Ground alarm panel". The contractor ran a green #12 THHN to the nearest water pipe. I thought he should go to within 5' of where the water service entered the building but that wording has to do with the GEC.
Posted By: renosteinke Re: Alarm Panel Grounding - 03/21/06 03:12 PM
George, what you describe is all to common, whether the appliance be a Ham radio, an antenna, a satellite dish, cable TV, or the phone box.
As I understand it, this grounding is simply there for lightning protection, and not in any way associated with clearing a fault current.

I would think that, were faults an issue, the thing would have a three-prong plug.

Even so, I believe code requires all grounds to be bonded to each other, while being pretty vague as to what this might mean. I've certainly never seen one of these things capable of accepting the #8 wire we're required to use here (for bonding pipes to the ground system).
As long as there is continuity between this wire, and the grounding system, I'd say he's met the requirement.
Posted By: montreal Re: Alarm Panel Grounding - 03/21/06 03:28 PM
I can't provide a code reference, but as a physicist, I can say that whenever grounding critical electronic equipment, whether it be for an alarm system, a stereo system, or a computer network, there is always a choice of many metallic paths that eventually find a route to the earth. Many of these options may not be good ones for the following reasons.

The primary purpose of grounding in electronics is to avoid having the metal box containg the electronic circuits "float" and thus unable to provide shielding from EMF radiation which generates noise in these circuits.

Since the failure of an alarm control circuit often is more critical than a failure of a computer network circuit, choosing the best route to earth ground is important.

The only way to be confidant that the ground wire from the alarm panel connected to the water pipe stands the test of time, is to bring that ground wire (without splices) directly to within 5 feet of the water entrance, assuming that this same water pipe is buried in the soil outside the building.
I personally have more confidence in the ground wire connecting the electrical panel to the copper rod which is driven into the soil, but I think the alarm manufacturer wants to minimize the cost of grounding by allowing a water pipe within the building to be substituted.

The alarm manufacturer is assuming that no segment of the chosen metal water pipe will ever be altered (by introduction of a threaded union with plumber's sealant) or replaced in part by a plastic pipe.

Almost as important, is the problem in electronics due to infamous "ground loops". This is a situation where multiple pieces of electronic equipment which are all interconnected to each other are also individually tied to the electrical ground of the building via different paths.

What happens is that even though each piece of equipment is grounded, the ground wire for each piece of electronic equipment can have a different distance (and possibly a different route) back to the main panel.

The difference in these ground paths causes a small (millivolts) amount of 60 hertz electrical voltage to be picked up within the ground wires which are acting as antennae. All the grounded electrical boxes are pulled to this same voltage(s).

Normally a few millivolts of voltage in ground wires wouldn't bother anybody. But for stereo equipment where the interconnections are often over unbalanced RCA cables and where the audible signals are measured in microvolts, we often hear the background hum in our loadspeakers. When this happens, it is necessary to ensure that only one piece of equipment (usually the receiver) is officially grounded and all the other equipment is "floating" by blocking the ground pin in the 3 pin plugs of all equipment except the audio receiver. Sometimes we even need to "float" the receiver to mimimize the hum.

For TTL and CMOS logic circuits such as used in computer networks or alarm control, the operating voltages are often between 2 and 5 volts DC, so if we have a ground loop generating a few millivolts in the alarm box, the control circuits have adequate immunity and the background hum will not interfere with the circuitry.

However, and this applies for all sensitive electronic equipment that is grounded, if there is a major electrostatic discharge within or nearby the building (lightning, high amperage short circuit, etc), the ground wires will pick up the pulse which in this case may be substantially higher than the few millivolts from ground loops, and there is a risk that our electronics will be fried. The use of varactors (as found in power bars) will provide the "surge protection".

But starting with a robust copper ground wire between the alarm equipment and the point where the water pipe enters the building and keeping this wire as thick as possible and its length as short as possible, will protect the alarm equipment in the best possible way.

As always, the ground connection to the water pipe has to be as professional as the ground connection at the alarm box, that is, solid connectors and no possiblity of corrosion ever reducing the electrical contact.



[This message has been edited by montreal (edited 03-21-2006).]
Posted By: Tom Re: Alarm Panel Grounding - 03/21/06 04:09 PM
George,

IMO, Fire alarm systems are required to be grounded even if there is no sticker in the panel alerting the installer to the requirement. 760.9

Again, IMO, this is not an equipment ground being used to facilitate the operation of an overcurrent device and all thats left for it to be is a grounding electrode conductor and it could connect to any point on the grounding electrode system or to any other grounding electrode conductor. If connected to a metal water line, then 250.52(A)(1) should apply. I think you're on the money for requiring the connection to be in the first 5 feet of pipe.
Posted By: gfretwell Re: Alarm Panel Grounding - 03/21/06 05:32 PM
Tom is on the right track. A water pipe, more than 5' from the entrance is not a "ground" unless you can demonstrate "... industrial and commercial buildings or structures where conditions of maintenance and supervision ensure that only qualified persons service the installation..." applies.

Connection to the EGC in the circuit would be code conforming. 250.110 250.134
If this is supposed to be a clean ground for the electronics I still get back to the IG principles (insulated conductor, run with circuit conductors and isolated all the way back to the ground electrode connection.
I see no way that a terminal, identified as a "ground" can be connected legally to a water pipe more than 5' from the entrance in a dwelling.

This is really a manufacturer's labelling problem. Just because a label says something stupid, does not negate your obligation to insure a code conforming installation.

[This message has been edited by gfretwell (edited 03-21-2006).]
Posted By: HLCbuild Re: Alarm Panel Grounding - 03/22/06 12:45 AM
Guys,

I disagree. The ground that the manufacturer is requiring is not part of the Grounding Electrode System. I would think if the manufacturer ask that the equipment be grounded to a water pipe and they don't specifically say "within 5 ft. of the entrance to the building", then they are just looking for the metal case to be bonded. Doesn't 250.130 (c) (1) and (2) allow a non-grounding receptacle to be replaced or a branch circuit be extended and be grounded to "any accessible point on the Grounding Electrode System or any accessible point on the Grounding Electrode System. It doesn't seem to say within 5 ft. of the entry to the building...or am I reading this wrong?
Posted By: montreal Re: Alarm Panel Grounding - 03/22/06 02:48 AM
HLCbuild,

I agree with you when you say that "the ground that the manufacturer is requiring is not part of the Grounding Electrode System."

In any case, I believe that the alarm system manufacturer is simply asking that his box be reliably grounded. For some reason, the manufacturer trusts the metallic plumbing system more than the electrical system.

Are there known instances in the electrical industry when the integrity of the electrical system has been compromised?

If the ground bus in an electrical system opens up, no one may ever know about it. But if a water line breaks, it won't take long for someone to discover it.

The manufacturer assumes that the risk of the water line being modified over time are low enough for him to favour a ground connection to the plumbing system (at any distance from the entrance) over the electrical system.

For the electrician to go the extra distance in assuring that the connection is within 5 feet of the water entrance is allowing the electrician to lower the risk of the alarm box ground failing below the risk level that the alarm manufacturer is willing to take.
Posted By: gfretwell Re: Alarm Panel Grounding - 03/22/06 03:24 AM
The instructions don't even say "metal water pipe" so it is clear the instruction is flawed. I haven't seen any metal in new construction here (electric or water) except the steel studs and they are not grounded either.
The code clearly says a metal water pipe is NOT a ground beyond 5' in a dwelling or any other place not "industrial and commercial buildings or structures where conditions of maintenance and supervision ensure that only qualified persons service the installation."
Posted By: shortcircuit Re: Alarm Panel Grounding - 03/22/06 12:12 PM
George Little, I started a discussion on this also...
https://www.electrical-contractor.net/ubb/Forum2/HTML/001625.html

I don't think the ground you are discussing is a equipment ground...

But if it is then...

I also would think physicle protection is a concern according to 250.120(C)

shortcircuit
Posted By: Scott35 Re: Alarm Panel Grounding - 03/22/06 11:30 PM
Quote

When the instructions with the "Household Fire Alarm" panel tell the installer to ground the equipment by connecting To a water pipe

I would like to know:
<OL TYPE=1>

[*] Does this equipment require to be BONDED to the GES,


[*] Does this equipment simply need to be Electrically BONDED to the system - the EGC,


[*] Is a supplimental Bonding Conductor required - which is Bonded to the GES at an "Effective Point", due to this equipment containing a MODEM, or similar device,


[*] If the instructions are just being as basic as possible - removing any liability on the Manufacturer's end.
</OL>

Semi-loaded questions, but not for trouble-starting purposes.

Have seen many FACPs with the noted "Ground Lugs", yet they all did not contain equipment which would warrant a bond to the GES.
They all used "Kind-Of Universal" enclosures, which resulted in all having the Ground Lugs - but only one actually needed to have a bond to the GES - the one with the event dialer (since the POTS circuit was dedicated to the FACP. the line pair was run directly from the TELCO's "PET" - and it is bonded to the GES, so does it really need to be bonded again?).

Have seen similar stuff on Alarm System Panels (Intrusion Alarms, etc.), Building Automation System Panels, and Audio Equipment for use in Commercial / Industrial locations.

Scott35
Posted By: George Re: Alarm Panel Grounding - 03/22/06 11:45 PM
"by connecting to a water pipe"

The waterpipe is connected to the GEC.

The GEC is connected to the EGC.

The EGC is connected to the "ground" screw.

Good enough for an engineer.
Posted By: HotLine1 Re: Alarm Panel Grounding - 03/23/06 01:25 AM
Guys:
Within your 'basic' resi FA/BA panels, all I have seen is a terminal on the board within the enclosure marked "Earth Ground". None of these panels had a 'ground lug/screw' mounted to the enclosure.

These are resi, lite comm panels installed by 'alarm contractors'; some local, some national or regional.

To make it clearer, there's a board with electronic circuits & components, with a terminal strip for connection of the various circuits/devices, and one terminal is marked "Earth Ground" on the schematic. I don't know if this is the type of panel George is refering to or not.

John
Posted By: JoeTestingEngr Re: Alarm Panel Grounding - 03/23/06 02:42 AM
Most of the systems I deal with just use it as a reference for the ground detector circuit. I've spent alot of time with one meter lead on ground and the other on signal circuit wires, hoping to find one a little closer to ground than others.
Joe
Posted By: George Little Re: Alarm Panel Grounding - 03/23/06 04:11 AM
John- That is exactly the type of panel I am referring to and usually it will specify to connect the afore mentioned terminal on the terminal strip to a grounding electrode. Ask any electrician or inspector and they will tell you that the nearest water pipe is not necessarily a qualifying electrode. There was a time about 10-12 years ago when we could rely on the water piping in a home for a ground and we used to just go to the nearest pipe when we wanted to ground something. Times change, code change and now we can't just go to the nearest water pipe.

Another thing that has happened is we still have old school technicians who insist that grounding their panels invite surges and damage their boards. The manufacturers of the equipment specify that they ground to a grounding electrode.
Posted By: HotLine1 Re: Alarm Panel Grounding - 03/24/06 03:29 AM
George:
Copper water piping within a SFD is bonded thru the water meter to the street side (within 5') of the point of entry, and bonded thru the first means of disconnect with the grounding electrode (rods) or ufer in newer construction. Based on this scenario, a connection at the water pipe (copper) is acceptable.

Some new resi is using PEX water piping, and red/blue non-metalic piping, which will require going to the GEC at an accessable location.

Would you agree with both comments above??

John
Posted By: gfretwell Re: Alarm Panel Grounding - 03/24/06 06:33 AM
John, you also have to look out for water softeners and whole house filters that may not be apparent when you look at the 5' "window" at the entry.
I still say the EGC in the circuit feeding the panel is the best bet. In most wood framed (non-Chicago) dwellings this *is* an IG.
Posted By: HotLine1 Re: Alarm Panel Grounding - 03/25/06 12:36 AM
Gfretwell:
Yes, the items you mention could 'break' the grd continuity of the water piping. And, yes, the GEC is my preferred choice, if I am doing the install.

However, FYI, the two 'offenders' in alarm inspections are:
NO earth ground.
NO bushing/grommet at cable entry into enclosure.

You may be shocked at some of the creativity I have seen.
#14 wrapped around a water pipe, similar to a 'choke'. Yes, it was green insul; no it was not terminated, just twirled around about 15-20 turns.
#14 under the 6/32 plate screw; a real work of art
#14 grn thru closet ceiling, not showing anywhere; pulled about 6" from above ceiling.
Small jumper from designated terminal to a sheetrock screw, that also secured the panel to the wall.
#14 grn shoved into the u-ground on the 'alarm receptacle'
and on and on.

Then there's the cable specialist, #10 grd from his splitter to a 2" pipe clamp....on PVC. Or, the lug tek screwed into the meter pan, or the downspout.

John
Posted By: gfretwell Re: Alarm Panel Grounding - 03/25/06 03:01 AM
I still don't understand why you canb't just connect to the EGC in the circuit feeding the alarm panel. Are these cord and plug connected or hard wired?
Posted By: George Little Re: Alarm Panel Grounding - 03/25/06 03:27 AM
John- I'd agree with your second example for grounding an alarm panel but I'd have reservations about the first example and also with Greg's fastening to the grounding conductor of the alarm circuit. It's been years since the Code change that said you are to ground to the GEC, panel feeding the circuit or the water pipe within 5' of where it enters the building. See 250.130(C) for some examples. I know the alarm panel is not listed there but you get the idea.
Posted By: jes Re: Alarm Panel Grounding - 03/25/06 01:42 PM
George,
If you are referring to the typical residential combination fire/burglar panel with a plug-in low voltage power supply it is a Class II system and is not required to be grounded if supplied with a LISTED class II power supply (which is the case if it is a LISTED alarm system). The grounding of the panel is primarily for transient protection for the electronics. You are correct in requiring the installer to do so as it is part of the listing and labeling (110.3B)of the panel (and I have not seen one that wasn't so labeled). Typically the specified grounding wire is relatively small...like 16AWG, so a even a 1/2" metal pipe is a far better conductor than that to transients. Yes, there are questions about whether a metal water pipe in the area of the panel has continuity to ground at all. That too is an enforcement issue and to your discretion. Personally I try to locate panels close to the service and make use of the GEC or some common bonding point whenever possible. Also yes, I have dealt with the arguments of the ground connection 'bringing' the lightning to the system. I consider it a nonargument. The system must be installed as instructed. I cannot fix all the other grounding and bonding issues the may adversely affect the performance. If the system dies from a lightning strike it likely would have with or without the grounding...so just do it.
Posted By: Paul O'Connell Re: Alarm Panel Grounding - 04/02/06 01:18 AM
George:
I think they can attach the ground anywhere on the domestic water system. I think we can trust the electrician to check and make sure he has ground continuity. THe 5 foot rule applies to the bonding of the service equipment. This would be equipment grounding and would be simular to the requirements for a seperate building or structure where you are assuring the equipment ground part. Normally the 120 volt feed to these panels will contain an approved egc. Now George that is my opinion and I am going to stick by it.
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