Surge coming in on camera wiring from remote building with seperate service

[shockme28139]

I have surge from lightning blowing out surge protection where transformer for cameras are plugged in and coming in on camera wiring. Would tying grounding together on services help?

 

[ActionDave]

A little more detail would go a long way toward some worth wile replies.

Let's start with what kind of surge protection.

 

[Volta]

You can get optical isolators for the coax with BNC connectors on them, and certainly power the cameras from the building they are associated with.

 

[junkhound]

.. surge from lightning blowing out surge protection ..... Would tying grounding together on services help?

Making an assumption your surge protection is MOVs, the most common type nowadays.
If protection is avalanche diodes, details different, but still the answer is probably not, as tying grounds together just improves the grounding, does nothing to increase the robustness of the surge protector.

The previous suggestion to use fiber optic coupling path is the best approach. Bigger surge protectors the next option, although those would be pretty big to survive and yet protect for a direct lightning stroke.
Here is more than you probably wanted to know about MOVs:

How MOVs made: Mix up some zinc oxide and barium oxide with some clay binders and roll out like cookie dough for cutout cookies. Thickness determines voltage. Cutout disks of a diameter for surge current rating - the bigger diameter, the more surge current prior to failure (integral of I^2*dt). Used up to 2-1/2" dia for some for EMP protection at missile silos. Flame spray both sides, attach leads - now you have an MOV.

How they fail: Each surge over the voltage rating 'turns on' the tiny diodes made of the grain boundaries of the zinc oxide particles. Every surge shorts out some of these. Over time the zinc oxide particles melt together (turn from crystaline to amorphous. When an MOV finally fails short, you can literally see a hole melted thru the device.

Now, when a big enough surge (or AC short current) flows thru the MOV, often times the leads or the metalization melts off or blows off or is detatched = OPEN.

Some mfg add a series fuse to the mov so the outlet strip continues to function if the MOV shorts, the best outlet strips have a resistor and neon glow tube across the fuse that lights if the fuse blows.