adding surge protectors in LB connector

[mikefamig]

My OPII can gets its ground from the conduit which gets its ground from the fuse panel which has multiple ground connections and its about 2 feet away from it.  An earth electrical ground can be defined / done in a number of ways.  Most important that you have a good ground to the can / panel...thinking its the first sentence in the HAI OPII installation manual.  Adjacent Leviton 42" can also is connected to same ground.
 

Pete
 
Have you considered the location of the surge protector device in relation to the OPII and the earth? In order for the device to protect the OPII it must have a shorter wire run between itself and earth than the run between itself and the OPII.
 
Mike.

 

[pete_c]

No. 
 
Lighting will take the shortest patch to ground; whatever or wherever that may be.  Power line surge is different.  Internal power surge (personally) is also different.  Difficult to guesstimate.
 
Well the OPII ground goes to a clamp a few inches away.  The conduit is a few inches away from the fuse panel.  The earth ground stake is about 2 feet from the back of the fuse panel which is also connected to the water ingress copper stranded cable.
 
Maybe or maybe not related....in the last 10 years....
 
I have had one lightning surge (via irrigation) which took out irrigation controllers.  (outdoor wire came from solenoid manifold ==> 100 feet + ==> two irrigation switches = =  > RS-232).  Took out irrigation controllers and not RS-232 device connected.  Lightning appeared to have only damaged Rain8nets.  Next door took out TV's, microwave, alarm panel, et al....such that maybe I was just lucky?
 
Also one internal surge which put 220 to 120 lines which tripped breakers and took out a majority of the older Insteon in wall switches.
 
What I saw ....compressor was on fire (well solenoid) leaked out all gas, shorted out two 120vac high amperage leads to solenoid....tripped breakers (3/4 of the fuse panel) and on its way to doing that burned up a majority of in wall switches at the time.  (only happened to Insteon and not UPB; but I replaced UPB switches anyways).  It did start as a pleasant hot summer rainy night.

 

[mikefamig]

Given that current travels on a wire at a given rate of speed........
 
The way I understand it in the event of an electrical surge where there is a voltage spike on an outside wire it will travel into the building and you want it to reach the surge protector as soon as it enters the building if possible (the sooner the better). At that point the current will continue seek ALL paths to earth and you want the path from the surge protector to the earth to be a shorter distance than the distance from the surge protector to the device that it is trying to protect. This allows the surplus voltage to be shunted safely into the earth before reaching the protected equipment.
 
If this was not true I could just put teh surge protector in the can with the Elk control and ground it to an electrical outlet, The problem is that my elk control is a good thirty feet or so from the AC load center and any earth ground.
 
Mike.

 

[JimS]

I understand that the wire from the LVLP to earth has to be shorter than the cable from the LVLP to the device that it is protecting (ELK). But what exactly constitutes earth? Does it have to be a stake in the earth? How about a plumbing pipe or metal BX cable in the house? If you use a BX cable does it have to be added to your length between the LVLP and the stake in the earth outside?
 
What I am asking is whether I can put the LVLP in the Elk enclosure and ground it to an electrical outlet or nearby plumbing? It is approx 30' from the elk enclosure to the load center and a ground stake. I have heard of coiling up wire between the LVLP and the elk but how do I calculate how much wire is needed?
Mike.

 
I am not sure where you got the idea that the relative distances are the main issue.  Ideally you would attach the protector, which tries to clamp the excess voltage, with as short as practical leads to both the signal and ground.  Then the leads (both ground and signal) would go from the protector to the protected device.  This is often not practical but is the best case.  Hooking up ground somewhere else lengthens the path.  Best case is the grounds are all bonded together where they enter the building.  Adding length to some wires so they are longer than other un-optimum connections is a poor methodology.
 
Pete's comment about using multiple ground rods raises concerns for me.  The NEC specifically prohibits that in most cases and has details of how they must be interconnected.  A ground rod on one side of the building is likely not going to have the same voltage as one on the other side during a lightening event.  It used to be common for TV and phone companies to just place their own (very small) rods but I think that is less common now.
 
What constitutes earth is a very good question.  The point is not so much to have everything at "ground" potential(voltage) but to have everything at the SAME potential (within the limits of the equipment).  
 
If you put the protector in the Elk can I would tie the protector ground to the Elk ground as closely as possible (right in the can).  Not knowing all the details of your installation that seems like a good way to go.
 
Just my opinion.  The usual disclaimers apply. 

 

[mikefamig]

I am not sure where you got the idea that the relative distances are the main issue.  Ideally you would attach the protector, which tries to clamp the excess voltage, with as short as practical leads to both the signal and ground.  Then the leads (both ground and signal) would go from the protector to the protected device.  This is often not practical but is the best case.  Hooking up ground somewhere else lengthens the path.  Best case is the grounds are all bonded together where they enter the building.  Adding length to some wires so they are longer than other un-optimum connections is a poor methodology.

 
The Ditek instructions specifically say to have at least three feet of wire between the lvlp and the device being protected to allow time for the lvlp to switch and also states that you must make the wire to the protected device longer than the wire to earth. I also know for fact that electrical current will take all available paths to earth and that the amount of current that flows on each path is determined by the continuity/resistance of the path. Relative distance is not the issue, resistance/conductivity is the issue and given the same gauge and type of conductor/wire the length becomes the determining factor.
 
 
 

Pete's comment about using multiple ground rods raises concerns for me.  The NEC specifically prohibits that in most cases and has details of how they must be interconnected.  A ground rod on one side of the building is likely not going to have the same voltage as one on the other side during a lightening event.  It used to be common for TV and phone companies to just place their own (very small) rods but I think that is less common now.
 
What constitutes earth is a very good question.  The point is not so much to have everything at "ground" potential(voltage) but to have everything at the SAME potential (within the limits of the equipment).  
 
If you put the protector in the Elk can I would tie the protector ground to the Elk ground as closely as possible (right in the can).  Not knowing all the details of your installation that seems like a good way to go.
 
Just my opinion.  The usual disclaimers apply. 

 

[mikefamig]

JimS
 
Believe me when I tell you that I wish that you were correct and that I was wrong about the installation of the lvlp. It would make my life much simpler and the installation much easier if I could just put the device in the enclosure with the Elk control and strap  the ground the the AC outlet. I welcome any and all input on this before I actually install the device.
 
Mike.

 

[pete_c]

It used to be common for TV and phone companies to just place their own (very small) rods but I think that is less common now.

 
Its one stake adjacent to the electric meter, phone box and cable box.  All three are clamped to the ground stake there.  Looks to be as old as the home (2003).  Also lightning arrestors are there.
 
I changed the above from 1-2 ground stakes to one ground stake as I looked outside.
 
So the meter is in front of the fuse panel in the basement.  The OmniPro 2 panel is next to the fuse panel.  The board and the can have ground connections (same).
 
Guessing here I agree with Jim relating to your Elk M1  / ground X2 (right?  one on the M1 and one on the can eh?)

 

[mikefamig]

Guessing here I agree with Jim relating to your Elk M1  / ground X2 (right?  one on the M1 and one on the can eh?)

 
I don't understand your question. I have installed an AC outlet in the Elk enclosure and it is properly grounded making the can grounded. The Elk panel is not grounded. Elk recommends isolating the panel common from earth ground.
 
Mike.

 

[pete_c]

Apologies Mike.
 
I am confusing myself.  I looked at my OmniPro II panel / can and secondary Omnpro II can. 
 
There is one ground connection on the panel itself but nothing in the can connected to earth ground.  The second HAI can gets it ground from the first HAI can (board).
 
My 42" Leviton can has one earth ground chasis connection in it.
 
I haven't really looked at the cans in a long time.
 
Found this old thread not directly related but similiar here from 2012 called Surge Protection Device on zone and other wiring to a shed

 

[Neurorad]

Your house should have 1 single ground. If you sink another ground rod, that new rod needs to be bonded to the existing earth ground rod. That SPD needs to use the existing house ground, not a new rod.

If there are 2 unbonded ground rods connected by any LV wiring, in the house, lightning may travel from 1 ground rod to the other, if the rods are at different voltage potentials.

Trenching a bonding copper conductor (8 awg?) outside, from a new rod to the existing rod, is often easier than running a new ground wire inside the house.

 

[pete_c]

Yeah the outside stake is bonded via a 10 gauge or so copper stranded wire to the chassis of the electrical meter which is bonded to the ingress of water pipe some 30 plus feet away.  Same size copper stranded wire gauge as on the inside.  First ground from outside stuff in via stuff like telephone, cable, lightning detector and roof antennas and other do whats stop at the stake before coming in to the home.
 
Yeah here I bonded the new SPD I purchased for the outside AC shutoff to the metal chassis box.  I just followed the instructions that came with the device.  The PITA part was the guage of the wire and having to rewire the HV electrical (I pulled all of it out first and replaced it with longer heavy guage wires).
 
I am guessing here then Mike can get his ground from the inside if the SPD is outside or mounting the SPD inside from whatever earth ground is inside or add a stake and bond it to the home earth ground?
 
What do you think Mike?  (are we waiting for Del to chime in?)

 

[mikefamig]

I'm considering putting the SPD in the LB where I can easily put it in series on the cat5e cable. Then just drill a small hole in the LB for a awg10 gauge wire from the SPD to the copper stake that is about 15' away from the LB/SPD. It is an existin ground stake that is bonded to the house's load center.
 
Mike.

 

[Del91574]

Its not to code to modify conduit bodies, and there's the fill issue.
Doesn't matter if its low volt, you still have to play by the rules.
 
Use a junction box.
Home Depot has 6x6x4 PVC jboxes for $12.

Fill does not apply to LV until you're dealing with fire alarm which is another ballgame and circuit discussion.

Also, the conduit is going to be considered a wet location so the "physical" rating of the device would mandate NEMA, not just the temp and 95% RH. In the discussion about multiple systems with their own or supplemental ground rods, that is now forbidden and only grandfathered. New installations must provide for a entire building ground connection for all building systems tied back to the ground electrode.

 

[mikefamig]

Fill does not apply to LV until you're dealing with fire alarm which is another ballgame and circuit discussion.

Also, the conduit is going to be considered a wet location so the "physical" rating of the device would mandate NEMA, not just the temp and 95% RH. In the discussion about multiple systems with their own or supplemental ground rods, that is now forbidden and only grandfathered. New installations must provide for a entire building ground connection for all building systems tied back to the ground electrode.

 
Hey DEL, where ya been we missed ya.
 
It's true that the conduit is a wet location and that does bother me and with that being the case it would do no good to replace the LB with a box because it would still be a wet location. I should just bite the bullet and put a small box inside the basement to be safe. I liked the idea of putting the surge in the LB because the wires are already spliced there  but if I make good splices in the house they will outlive me. The input I get here really helps me think and make decisions.
 
Mike.

 

[Del91574]

Been very busy. Got a lot going on between WCSU, UCHC, YNHH, SRC and GCC at the moment.....with the extra excitement of a 25 story building's fire alarm being completely down courtesy of a co-worker not understanding tech notes and how to proceed updating firmware.
 
There's a difference between an enclosure and a conduit body. In the case of an enclosure, above grade it will not be considered a wet location. Conduit is. If dampness is more of the concern with corrosion, I'd still put the enclosure, then do what is necessary within the space to facilitate an install.  For that matter, you could actually run the LV and HV within the same enclosure if considerations are met.