Shielded cable gauge for strobes

Camillo · #1 10-13-2008, 08:40 AM

Hi. I bought a strobe power pack from Creativair. I ordered a kit for 3 strobe lights. It came with 60' of shielded #22AWG wire (CAROL (R) 22AWG -- C251 7A -- 75C E111240-8 CM(UL) C(UL) CMH.

For the distance of the 9A, I calculated a 14AWG wire. 22AWG is far lower than 14. Shall the voltage drop be calculated only from bus to power pack? If so, each single wire run from power pack to strobe light will be OK with #22AWG and only the main unshielded wire would be a wider size. Or shall I use #14AWG shielded wire for all the high voltage wire routing?

Thanks.
Camillo

noelf · #2 10-13-2008, 09:16 AM

If you are talking about a Wheelen strobe system, the shielded wire is used between the power pack and each strobe flash tube. The Wheelen web site has a good set of documentation for their units.

I have no experience with other brands...

DGlaeser · #3 10-13-2008, 11:22 AM

I concur with 'noelf' - the shielded wire is to connect the flash tubes to the power supply. The 'high voltage' is very short (milliseconds) so the 22AWG wire will work fine.
As you suspect, the voltage calculations should be from the bus to the power supply, and those wires don't need to be shielded.

Camillo · #4 10-13-2008, 12:56 PM

Yes, it is the Whelen system. Although I read Bob's book a few times, there are still aspect that are not obvious to me!
Thanks.
Camillo

LifeofReiley · #5 10-13-2008, 01:23 PM

Quote:

Originally Posted by Camillo

Yes, it is the Whelen system. Although I read Bob's book a few times, there are still aspect that are not obvious to me!
Thanks.
Camillo

My System 6 Whelen System from Van's came with 18 awg shielded wire FWIW...

Canadian_JOY · #6 10-15-2008, 01:49 PM

Wire gauge for shielded wires between strobe power supply and xenon flash tubes is actually more important than one would think. The power supply puts out a pulse of high voltage/low current energy. It's a pretty sharp pulse and we naturally tend to think that because it's of fairly short duration that it doesn't require fat wires to carry it. However this isn't entirely true since all electricity obeys Ohms laws, whether it's in pulse form or any other form. True, pulses also obey some other laws that make engineering for their use a little more complex, but in the end it's Ohm that'll get ya. Many strobe manufacturers recommend 18ga wiring between the power supply and the flash tube, and for very good reason. Loosing a bit of energy in smaller wires may seem like no big deal, but can in fact result in significantly less brightness from the flashtubes. Since we want our aircraft to be seen, more energy at the flashtubes is what we really want.

BTW, Whelen also uses Belden cable for some of their type-certified installations. I have no idea how they get away with this since the stuff is NOT tefzel or anything like it. My airplane is wired with MIL-C-27500 tefzel twisted shielded triple wires from the single strobe power supply mounted under the passenger seat out to each wingtip. Total cost of using this wire was about $30, not enough to break the bank...