Awos

[codewarrior321]

Hi I have a oportunity to bid on All Weather Operation Stations and have being ask to provide Site Survey as to the electrical installations, This will be use to estimate the projects. Their are 15 sites all with in a 100 mile radius of each other. I estimated around 8 hrs per site, broken down to 2 hrs at survey site,2 hrs for travel back and forth, 2 hours for reports, 2 hours to estimate.
What do you guys think of this, all opinions welcomed.

 

[codewarrior321]

Well I found some info and the information Is very intensive in the grounding and bonding protection for lightning,RMC wiring method to protect the communications,power and sensor wires from physical and lightning strikes,Bond everything, All sensor pads must have a #4/0 bonding conductor.The grounding is taken care of by equipment grounding conductor ran with the feeds,only exothermic weld for all the bonding splices and any location that will not be accessible,Minimum 3/4 rod(I still do not know if it has to be SS . Must run a bonding conductor to main electrode system from the AWOS grounding system,ECT. Meeting with the engineer Tuesday.

 

[ceb58]

Be prepared for a lot of digging and cad welding. On our communication towers we use copper clad grods. Check the specks. as to what they want as far as conductors. We use #2 7 strand hard drawn bare copper or #2 solid tin coated copper. Also check to see if they require testing of the system to obtain a certain ohm #. This may require you to sub this out. Bottom line is they will be looking for the cheapest bid As far as time to estimate the first one will take longer. Once you get a general material list with prices then the others will go faster since most sites will be very similar.

 

[codewarrior321]

Faa

Faa

Hi thanks for the reply, The FAA-STD-019d manual that talks about lightning,grounding,bonding and surge suppressor.mention, in the manual it makes reference to having certain minimum ohms like you also stated.

 

[Power Tech]

The testing is usually required to be certified by an outside contractor.

In the testing I have done it took 4, 10' ground rods 10' apart, cadwelded to get a reading close but not as good as the cold water.

 

[ceb58]

The testing is usually required to be certified by an outside contractor.

In the testing I have done it took 4, 10' ground rods 10' apart, cadwelded to get a reading close but not as good as the cold water.

Ours, after all the grods, bare copper in the ground, bonded to the tower legs, fence post we must have 5 ohms or less. Then any thing metal inside is bonded to a halo that is tied in to the system.