PM Q: Grounding Discharge Block in 70A

[George Stolz]

WHY does nec70A rule require that grounding blocks (discharge units) be mounted as close as posssible to point where lead in cable enters house?

I don't have 70A, but if I were to venture a guess, I'd say so that the lightning travels down the side of the house instead of into it. We'll see what the big minds on here think.

Edit: It's late and I'm tired. 70A is the NEC, isn't it?

 

[hurk27]

Wonder if he meant a gas discharge unit? while I have seen gas discharge units placed at the weather head or meters, I have never seen any closer, most air discharge units are mainly used up on the primary lines, and for the most part right at the transformer, unless it is a gas discharge unit which is placed right at the service entrance? TVS are at the meter, panel, or point of end load. all of which require leads to Earth kept as short as possable, so maybe this is what hes talking about?

 

[hurk27]

Whoops guess I should read better:roll:
and yes they want the CATV cable to be protected at the entrance to a house to prevent as much as possable, lightning from coming into a house, and mounting it close to the main service and creating a single point entry will even be better as lightning will treat the cable and power as one conductor and this will stop any current from lightning from flowing into the house, also installing phone here will also help.