Water Heaters - Temp/Pressure Relief piping

I am happy working with copper and want to pipe the PRV to the outside as it should be on a water heater for a friend.
It is a Sheetrock/stucco wall so no problem with making a hole.
But I'm trying to find info about how the pipe should terminate outside.
If I go straight through and have a down section how long should it be.
Also there is wiring going through the wall at the same point at the internal floor level. Looks like phone/cable coax etc rather than power. Would I be OK to just run the PRV pipe down past this or should it go horizontal for a short section?

Thanks

I don't think the pipe would cause any problems to the coax cable but I would think the down spout should be close to the ground for safety reasons since it would be shooting hot water.

Most codes require that downpipe to terminate between 6" and 12" from the ground.

I would not recommend this if you are in a cold climate. If it were to have a small leak, that went un-noticed, causing it to freeze, and there was a faulty hi limit control on the heater, you may just be able to watch your water heater go through the roof. I know it sounds like a lot, but if you have seen the movies I have about water heaters, I wouldn't want to constrict the opening of the relief valve or RV tube. Including Ice