Industry Forums > Wireless Service Providers > Outdoor AC Surge Suppressor

Outdoor AC Surge Suppressor

I always recommend much lower power fanless VIA EDEN boards outdoors but many have used mini-ITX: »Outdoor Mini-ITX Boards

*** Even far away lightning will induce surge in the long AC cable, so you have to provide very robust protection at building entry end on all conductors of the cable ***

Citel makes outdoor AC surge protectors with gas discharge tubes (GDT) and sometimes additional MOV inside. Check this page first and show the NEMA models in the service entrance tab to an electrician. »www.citelprotection.com/citel/ac_surge.htm

You should provide separate surge protection at that end connected to tower grounding system but do not let your electrician "bond" the tower ground to your building ground. A long exposed bonding cable will provide an unprotected path for massive lightning surge current that will fry any protection device at your building entry in a few milliseconds.

A very safe method will be to use 24V/3A AC transformer connected to "code-compliant" outdoor AC outlet close to the building entry point. The 24V AC can be converted to 12V/5A at the mini-ITX. You will find UL/CSA approved 24V AC transformers and 24VAC/12VDC converters at alarm industry distributors.

reply to lutful

reply to ibliz
If you need to provide surge supression on AC, use something built for this kind of thing. I always suggest, and pick first, products by Transtector. They do not make things that are cheap, so they are more expensive. But I can tell you that where other products fail, theirs will not.

120V protection:
»www.transtector.com/productdetai···1101-338

And bond your ground systems....
--
Using a non-ports-system OS is like masturbating with a cheese grater


"No job is so important, and no service is so urgent that we cannot take the time to do it safely."
-- AT&T

reply to John Galt
I suggested 24V AC mainly to avoid NEC boogeymen.

I hope my many posts consistently declare that all conductors of all cables need to be surge protected at the building entry. Does not matter if it is 12V or 24V or 48V DC or AC.

There is no argument about bonding either ...

Bond all surge protection devices for all cables entering the shack and ground with shortest possible cable.

Bond all surge protection devices for all cables entering the home and ground with shortest possible cable.

With a M.Sc in EE, I hope I am capable of understanding the fundamentals as well as you are. I worked almost 20 years in IC and system design that always included adding ESD/surge protection.

But it is true that my "still evolving" understanding of outdoor lightning/surge protection comes from mainly self- study of available literature and a few field experiments last summer.

I know most WISPs continue following the current NEC wisdom but I only want people to think a bit before connecting that long "bonding" cable between the two grounding systems.

*** Clarification for very common PoE CPE setups ***

Please bond the grounding lug of PoE surge protector to building safety ground with shortest possible copper strap or cable.

My dissenting comments only relate to "bonding" distant WISP equipment to your building safety ground using a long cable.

reply to AMD Phreak

Johns suggestion was the same one I was thinking of.

reply to John Galt

I agree.

People should not put a Tripp-Lite in a NEMA4 box on their tower and consider their equipment and house protected.

Yup. I just contacted Tripp-Lite and they do not recommend any of their surge-suppressors for outdoor use.

After doing more research on the subject, I find it is much safer and less hassle to just use DC to power tower-top equipment. I am going to get this DC power protector :

»www.polyphaser.com/productdetail···IX-1DC12

It is weatherised too (hopefully that mean it is outdoor rated). Anyone ever use this before ??

The downside is, I will have to use at least 14 AWG size wires for the DC powerline in order for the voltage drop to be within the tolerable range. Anyone thinks this is a bad idea ?

Those are good units. I have used the CAT5 models. They have a rubber gasket around the lid and the gland nuts on the ends seal super tight. I have not had to replace any parts yet, but the modular design allows fast change-out of blown protectors.

If 14AWG is required to mitigate the DC power drop, then so be it.
--
"No job is so important, and no service is so urgent that we cannot take the time to do it safely."
-- AT&T

Hi AMD Phreak,

Does the Polyphaser IX series come with detailed instructions manual ? The polyphaser site dont give much technical information on their products.
When you said modular design, do you mean we can buy spare protector ?

I took a look at the CAT5 protector and I might replace my cheap-looking Citels with Polyphaser. But how come they only have 4 connector terminals on each side of the link ? Also do you have to use punch-down tools to connect the CAT5 to the unit ?

From what I recall it did not. The terminal blocks on the protectors are labeled clearly though.

As far as modular: Yeah you can just order the spare PCB protectors and keep a set on hand. You don't have to order an entire unit.

For the CAT5 units, you use set screws. There are 4 pairs per side. It's set up just like the older Canopy Transtectors, if you ever have used those. Just keep your pair twists all the way until you enter the block.
--
"No job is so important, and no service is so urgent that we cannot take the time to do it safely."
-- AT&T

reply to ibliz
Not familiar with that particular unit, but I've used a lot of Polyphaser stuff over the years, mostly on RF and telco lines.

But the single most important thing with lightning protection is your grounding/bonding system.

Polyphaser sells a great book on lightning protection. Best $20 you will ever spend. I HIGHLY recommend it.