Wireless Access

What level of protection is afforded by the built-in lightning arresters in ap-275 and ap-277?

Do they protect the AP itself, like offboard arresters, such as AP-LAR-1?

Are they designed to protect from 'near-misses' or direct strikes?

Would it be accurate to say that changing from an 'all-copper' ethernet link to the switch, to a 'part-way-copper, part-way-fibre' link using a media converter, would offer better protection to that switch?

The built in protection is sufficient to handle ambiet and surge on cables below 2m. Anything over 2m and it requires LAR's for grounding before any surge enters the AP.

No they will not protect against direct strikes. 

The entire reason for having LARs is to protect the internal circuitry of the AP from ambient surge, static buildup, etc. The 274 has beefier circuitry to handle on it's own direct attach antennas or cables up to 2m. Over that you need LARs to offload the static via the chassis. 

The Chassis is grounded so that any near miss or direct strike provides a more direct path to ground than the ethernet cable does (which goes into your building). So the 27x chassis should ALWAYS be direct grounded on the grounding lug. 

Powered fiber will not be as favorable to a lightning strike as a direct ground lug.

Many thanks Jerrod  :)

In this case I'm only looking at the APs with built-in antennas (275 / 277) - but useful info on 274 with external antennas too.  Thanks again and have a good weekend.

So in that case, proper grounding of the AP on the lug is required. From there, it's a local CE determination if you need a separate Cat5 lightning suppressor on the ingress core where the Cat5 goes into the building. We recommend PowerDsine's Cat5 suppressor as we know it doesn't affect POE or Gig transmission rates.