It seems to me that a wireless connection provides the ultimate isolation.

On 5/16/2015 1:39 PM, Harold Hallikainen wrote:
> I'm working on an application where contact closures will be sensed by a
> PIC inside a building, but the contacts are outside (perhaps tens of
> meters away). What sort of protection for the inputs is suggested? What
> sort of protection is required by regulatory standards for equipment
> connecting to outside wiring? The outside wiring would likely be buried,
> but lightning could still induce currents into buried cables. Opto
> couplers are one way to get the isolation, but then you have to power the
> LEDs with an isolated supply. Ideas?
>
> Thanks!
>
> Harold
>
>
>

--=20
John Ferrell W8CCW
    Julian NC 27283
  It is better to walk alone,
than with a crowd going the wrong direction.
                   --Diane Grant


--=20
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