Length of braided cable from bar to SPGP?

[zero_frequency]

I'm in the process of mounting a SPGP on the exterior wall of my home where I will run the "protected" side cables into my shack. It's really the only place I can mount it.

My question is, when running braided cable from the ground bar to the SPGP (all interior), I would have to run this cable across two walls via a corner, so there would be a distance of no more than 20', max. I'm wondering if this is too far from my rig to the panel where I would then drop straight down with a flat cable attached to a ground rod. Would this be considered excessive or not a problem?

Any thoughts much appreciated.

 

[prcguy]

Depends on what your trying to accomplish and if you have local rules governing electrical installation. In the US if you add a ground rod in addition to one at your main AC electrical panel you must bond the new rod to the main ground rod with no less than 6ga copper wire. If your inside ground bus is intended to bond all your equipment together for human safety then 20ft of large gauge wire like 10ga or bigger should be fine, after you bond your ground rods together.

If you are going for lightning protection that's a completely different topic that needs some engineering and you may never be able to protect your equipment from lightning damage due to complications and expense. But one thing is for sure, if you bond your equipment to a new ground rod and that new rod is not bonded to the main AC panel ground you will probably increase the damage from a lightning strike.

 

[k6cpo]

What's an "SPGP?" Not everyone understands all acronyms and Google doesn't give any information.

 

[zero_frequency]

Hi k6cpo,

Single Point Ground Panel is a term I got from the ARRL Grounding book, the entry panel into the shack.

 

[zero_frequency]

Hi prcguy,

Thanks for your reply. Yes, I am in the US, Texas. I am trying to tackle electrical power safety and ligthening protection, and will work RF protection after I get these in.

You bring up a good point I haven't been clear on. The panel for AC is in a room inside the house and I can only guess that it's grounded to the rebar in the foundation, otherwise, no where is there a ground rod around the home that I can see that would lead to the panel. It's foundation all the way around. So I'm not exactly sure how I would bond the main ground w/ that of the SPGP.

Initially I'm must going to put up a wire, one day a tower, but not for now.

 

[mmckenna]

It's foundation all the way around. So I'm not exactly sure how I would bond the main ground w/ that of the SPGP.

There will be a ground point where the utility enters your home. Probably an electrical meter there.
With a foundation like that, it's possible that the ground is just a piece of rebar sticking up out of the foundation. That's perfectly acceptable from a code point of view.

 

[prcguy]

Hi prcguy,

Thanks for your reply. Yes, I am in the US, Texas. I am trying to tackle electrical power safety and ligthening protection, and will work RF protection after I get these in.

You bring up a good point I haven't been clear on. The panel for AC is in a room inside the house and I can only guess that it's grounded to the rebar in the foundation, otherwise, no where is there a ground rod around the home that I can see that would lead to the panel. It's foundation all the way around. So I'm not exactly sure how I would bond the main ground w/ that of the SPGP.

Initially I'm must going to put up a wire, one day a tower, but not for now.

Grounding stuff in a radio room that is far from the AC entry panel can be a big problem for lightning protection but not for meeting NEC for human safety. Grounding to the point of surviving a direct lightning hit is not realistic unless you planned that before the house was built and had a grounding system specifically designed for lightning protection. Retrofitting an existing house electrical system to perform at the same level is just not practical.

You can however install hardware to protect from nearby strikes to a power pole down the street protecting your AC panel and to some extent your receivers from high voltage induced onto your antennas. For direct lightning hits its better to know and understand your not protected and disconnect antennas and power plugs when a storm is approaching.

 

[k6cpo]

Hi k6cpo,

Single Point Ground Panel is a term I got from the ARRL Grounding book, the entry panel into the shack.

Thanks. I have that book. I just haven't read it in detail. I appreciate the clarification.