Routing Strobe Light Cable

F1118 · Post by **F1118** » Sat Mar 08, 2003 7:10 pm

Anyone have a good way to route my power cable to my deckblaster strobe that I have mounted above the rear view mirror in my Crown Vic?

Macon Sparks · Post by **Macon Sparks** » Sat Mar 08, 2003 7:47 pm

If the strobe interfering with the radio is not an issue, here's an installer trick.

The factory cable is round and has a shield over the three conductors to eliminate the whining in the radio speakers. That cable is not very handy for running above the headliner because it usually leaves a hump.

Go to a trailer supply house or automotive store and buy some 4 - conductor trailer wire. It's flat. Peel off the extra unneeded wire. Use the three remaining leads run up through the A-pillar (passenger side if you have a spotlight for the driver) Duct tape it to the roof underside. Extend your lead from the light if nessessary so the connectors meet under the headliner, out of sight.

If you are wiring a light that has two strobe tubes leave the four wires intact and combine the grounds. You only need four wires to power two strobe heads.

Used this trick several times myself.

jim · Post by **jim** » Sat Mar 08, 2003 9:04 pm

Unsheilded strobe cables......that's a GREAT way to deploy your airbag unintentionally. It's also a great way to get EMI into ABS/BCM/PCM/DCL/TCT/DIC and many other systems!

007 · Post by **007** » Sat Mar 08, 2003 9:54 pm

Unshielded strobe cable?

Um, like...............NO!

Use the factory 3 conductor shielded strobe cable and tuck it nice into the headliner. It is not a problem in the CV to do so.

Hello, McFly? Anyone home?

Jay G. · Post by **Jay G.** » Sun Mar 09, 2003 12:37 am

Important tip with strobes - Make sure you use SHIELDED cable, 18ga Minimum, and it MUST be rated for 300volts - If not, it will melt!!!

Be careful! Spend a few bucks, and it will work out well. Dont spend a few bucks, and watch your whole investment BURN!!!

FFParamedic571 · Post by **FFParamedic571** » Sun Mar 09, 2003 6:04 am

Since it a Deckblaster. It shoud be self contained. Tuck the cord in behind the headliner. If you want to get fancy Remove the "A" pillar trim, unscrew the flip down sunvisor and mounting clip It takes a torx T-20 tip. Drop the headliner Tape the cord to the roof with a good duct tape. Run the cable down the "A" pillar behind the trim. under the dash to a switch of your choice.

nmfire10 · Post by **nmfire10** » Sun Mar 09, 2003 7:43 am

Macon Sparks wrote:The factory cable is round and has a shield over the three conductors to eliminate the whining in the radio speakers. That cable is not very handy for running above the headliner because it usually leaves a hump.

Whats worse? That bump you really can't even tell is there, or

Jim wrote:that's a GREAT way to deploy your airbag unintentionally. It's also a great way to get EMI into ABS/BCM/PCM/DCL/TCT/DIC and many other systems!

DO IT THE RIGHT WAY! Use shielded strobe cable.

KitN1MCC · Post by **KitN1MCC** » Sun Mar 09, 2003 8:06 am

well if it i just the power cable. for a self contained strobe it should not matter if it is sheilded just use the correct gague for the load

nmfire10 · Post by **nmfire10** » Sun Mar 09, 2003 8:42 am

KitN1MCC wrote:well if it i just the power cable. for a self contained strobe it should not matter if it is sheilded just use the correct gague for the load

Right, For power it doesn't matter as long as the gauge is correct. But Macon Sparks is recommending the use of trailer wire for actual strobe outputs.

jim · Post by **jim** » Sun Mar 09, 2003 2:48 pm

#24/3 foil shielded cable is just fine for strobes. Pierce, McCoy Miller and many other manufacturers use #24- and it's much smaller. Remember- there's little current on this cable.
30W/500V=0.06A current on average per lamp.

vindoty1 · Post by **vindoty1** » Wed Mar 19, 2003 10:50 am

the best thing for a deck blaster is to make a small hole in headliner rout the cable to the post straight down behind the plastic to the floor,and then over too switch box,or pwer outlet.

Bob W · Post by **Bob W** » Fri Apr 11, 2003 5:16 pm

jim wrote:#24/3 foil shielded cable is just fine for strobes. Pierce, McCoy Miller and many other manufacturers use #24- and it's much smaller. Remember- there's little current on this cable.
30W/500V=0.06A current on average per lamp.

Except..... Using your example of 30 watts average and 500 volts when triggered, and assuming Double Flash where the second flash is 50% of the power of the first flash, and there's one Double Flash sentence applied to the head per second. That means that the first flash is 20 watts, and the second flash is 10 watts. Soooo, peak current during the first flash is 40 amps, and peak current during the second flash is 20 amps (Remember that a strobe's on time is 1 millisecond - give or take). Voltage drop on a 20 foot 24 gauge cable (It's one ohm) would be 40 volts on the first flash, and 20 volts on the second flash. Average power is now 27 watts versus the 30 you'd get directly connecting the tube to the power supply. In this, I don't take into account that the current in the flash tube will likely be lower because of the lower anode voltage, so, the power will likely be lower than 27 watts. I don't know how to calculate it.

jim · Post by **jim** » Sat Apr 12, 2003 6:25 am

40 amps? How, exactly, did you come up with 40 amps? Was it a late night? Too much crack?

40 amps @ 500 volts???

So you are telling me that when a strobe tube fires, there is a 20KW surge?

When you speak of the second, third or whatever flash of the series: this is irrelevant. The strongest or most powerful flash is what matters- not weaker ones, as we are talking about PEAK POWER and not absolute joules.

Um..........no! Sorry. There is NO 40 amp surge on a strobe HV lead- period. There is also NO 40V drop.

With your "theory" in mind, if you have a 1300 foot radio tower with 6 level strobe lighting, the top-most light at 1300' would barely flash.

#24 is totally adequete for any ladder truck, ambulance or police car.

nmfire10 · Post by **nmfire10** » Sat Apr 12, 2003 6:51 am

40 amps? Can get some of whatever your smoking? I could make some good money selling on the street in the city.

Bob W · Post by **Bob W** » Sat Apr 12, 2003 8:49 am

jim wrote:40 amps? How, exactly, did you come up with 40 amps? Was it a late night? Too much crack?.

Enough with the insults.

jim wrote:40 amps @ 500 volts???

You're right, it actually should be higher, but I factored in the ESR of the capacitors at about 10 ohms, and the impedance of the flashtube which is around 1-2 ohms after being triggered.

I=E/R = 41 amps = 500(volts)/12(ohms)

jim wrote:So you are telling me that when a strobe tube fires, there is a 20KW surge?

Yup. Remember, we're talking about the peak current during the flash. The flash width is only about 1 millisecond wide, so peak is everything as far as getting the available power to the tube. 20 Kw / 1000 is about 20 watts averaged over a second. Think Radar - pulsed radar, like marine radar. They are rated at like 4 Kw. That's the peak power of the pulse. Average it out, and it's around 10 milliwatts. This is why a strobe is what it is. Lots of power for a very narrow interval. Where do you think that 4 amps at 12 volts is going. All that energy is dumped in a 1 millisecond window. I base this all on a real power supply, like a Whelen UPS-60 meaning that it's got around 150 uf of capacitors at 600 volts, and not some 10 uf teeny little strobe. BTW, that would be 27 Joules per flash.

jim wrote:When you speak of the second, third or whatever flash of the series: this is irrelevant. The strongest or most powerful flash is what matters- not weaker ones, as we are talking about PEAK POWER and not absolute joules.

I threw in the second value because the voltage is lower during the second flash because the caps aren't fully charged, and consequently, the current is lower.

jim wrote:Um..........no! Sorry. There is NO 40 amp surge on a strobe HV lead- period. There is also NO 40V drop.

A pair of 24 gauge wires is 50 ohms per thousand feet. 20 feet is 1 ohm. Voltage drop across 1 ohm at 40 amps is 40 volts.

jim wrote:With your "theory" in mind, if you have a 1300 foot radio tower with 6 level strobe lighting, the top-most light at 1300' would barely flash.

That's why a Honeywell flashguard 3000 is only good for 500 feet on #10 cable. This is a system that operates at 1 KV. The capacitors are in a box at ground level. To further, you need the capacitors at the flashhead, which is what is done on large tower systems. The charging current goes up on relatively small cable, and the dump current occurs locally.

jim wrote:#24 is totally adequete for any ladder truck, ambulance or police car.

Not really. The resistance increases the discharge time which means the peak brightness is lower. The arc stays up longer, so, at short range, you may not see much of a difference because your eyes are fooled.

When I get a chance, I will do some scope captures across a 1 ohm resistor, and post them here. I've done it before, but I can't find the files.

jim · Post by **jim** » Sat Apr 12, 2003 12:26 pm

None of what you're saying has ANY relevance to anything.
When you are speaking of a surge which last for NANOSECONDS, this DOES NOT MATTER for sizing the cable- period. No matter what your scope says. Instantaneous peak power for nanosecond or microsecond bursts means nothing for what we are doing with strobe cable.

If what you are saying is really true and correct, Whelen, Tomar, Federal, NOVA, Sound-Off, Code 3 and all of the other companies are wrong about their engineering and YOU are right. If this is all true, all strobe tubes should have a 4/0 (four-ought) three-pair service entrance cable going to them. Take apart a power supply and look at the size of the traces on the 3-pin connector. They are smaller in total surface area and internal area than any #24 (or smaller). A 100watt radio can send it's RF through a #24 solid wire, but don't try to run 100watts @ 12VDC through the same #24.

When was the last time anyone has seen a strobe cable get warm from resistance during a 20KW microsecond-long burst? I haven't and I know that nobody else has, either.

McCoy Miller, Braun, Pierce, KME, LaFrance, and AEV are all wrong in their OEM design of using #24 cable FROM THE FACTORY to operate their strobes on newly built vehicles, too.

I think that all of these companies had better hurry up and set up a consultation with you so they can get their products functioning as they should.

All of what you claim may be the case in a laboratory condition when measuring every detail of everything, but for service, installation and repair means nothing at all. The bottom line is that #24 will work, as the operating current is well under 100ma.- no matter what the initial surge is.

Bob W · Post by **Bob W** » Sat Apr 12, 2003 3:15 pm

jim wrote:None of what you're saying has ANY relevance to anything.
When you are speaking of a surge which last for NANOSECONDS, this DOES NOT MATTER for sizing the cable- period. No matter what your scope says. Instantaneous peak power for nanosecond or microsecond bursts means nothing for what we are doing with strobe cable.

It has EVERYTHING to do with what a strobe is. The correct time interval is milliseconds.

jim wrote:If what you are saying is really true and correct, Whelen, Tomar, Federal, NOVA, Sound-Off, Code 3 and all of the other companies are wrong about their engineering and YOU are right. If this is all true, all strobe tubes should have a 4/0 (four-ought) three-pair service entrance cable going to them. Take apart a power supply and look at the size of the traces on the 3-pin connector. They are smaller in total surface area and internal area than any #24 (or smaller). A 100watt radio can send it's RF through a #24 solid wire, but don't try to run 100watts @ 12VDC through the same #24.

Actually,

Tomar http://www.tomar.com/pdf/TomarCatalog.pdf says 16 gauge. Where are you seeing 24 gauge wire? A short jumper in a head? The resistance in a short jumper isn't significant.

jim wrote:When was the last time anyone has seen a strobe cable get warm from resistance during a 20KW microsecond-long burst? I haven't and I know that nobody else has, either.

It's not going to get warm. Remember, according to my previous calculations, you're only burning up a couple of watts ON AVERAGE along the entire length of the cable. The resistance of a 16 gauge cable 20 feet long is .162 ohms. This results in a drop 6.49 volts using the same 40 amp peak.

jim wrote:McCoy Miller, Braun, Pierce, KME, LaFrance, and AEV are all wrong in their OEM design of using #24 cable FROM THE FACTORY to operate their strobes on newly built vehicles, too.

Again. how long? Inches?

jim wrote:I think that all of these companies had better hurry up and set up a consultation with you so they can get their products functioning as they should.

I'm sure their engineers are well aware of the facts.

jim wrote:All of what you claim may be the case in a laboratory condition when measuring every detail of everything, but for service, installation and repair means nothing at all. The bottom line is that #24 will work, as the operating current is well under 100ma.- no matter what the initial surge is.

Ok. Operating current is 100ma.? You don't have a scope. Put a 200ma. fuse (this is 200 % of what you believe current to be) the in series with a head, and let her rip. PLEASE, and this is important, put something significant between you and the fuse. It will likely explode. Be sure to call Whelen, Tomar, Federal, NOVA, etc. next Monday and ask them about 20 foot runs of 24 gauge shielded phone wire for heads. Who's wrong now?

nmfire10 · Post by **nmfire10** » Sat Apr 12, 2003 3:55 pm

My cat's breath smells like cat food.

jim · Post by **jim** » Sat Apr 12, 2003 4:12 pm

Okay....as per usual.....YOU are right.....I am wrong.....

My name isn't Jim, either.

YOUR scope is God.

Oh- I DO own a scope, too.

jim · Post by **jim** » Sat Apr 12, 2003 4:24 pm

I almost forgot-

As for the lengths for OEM cabling.....um....

A 100' Pierce ladder truck is in the neighborhood of 48' long and the PS is mounted behind the officer's seat. This makes a cable run approx 32-38 feet from the PS to the rear strobes- not inches as your laboratory and bench models show.

An ambulance's PS is in the rear service cabinet- about an 18 foot run through everything to the grille and maybe 8-10 feet to the rear of the box.

I'll call Pierce on Monday and tell them that Bob said all of their engineers are wrong and what they use on literally thousands of trucks IN SERVICE THROUGHOUT THE WORLD cannot, will not and do not operate properly because your scope told us so.
You are going to cost the OEM vehicle manufacturers hundreds of thousands of dollars to recall all of these vehicles to install the proper #16 cable since their #24 cannot handle the 20KW of current for 1/100000000 of as second and will vaporize when the lights are turned on.

Maybe if we were to cryogenically jacket the #18 and #20 cables that come with most strobes, we could somehow keep these wires from melting down from the 20KW "surge."

Some people.

nmfire10 · Post by **nmfire10** » Sat Apr 12, 2003 4:25 pm

According to the Iraqi Minister of Information, strobes do not use electricity and they do not require wire either. There is no power supply and small jumpers do not exist.

There, your both wrong.

Bob W · Post by **Bob W** » Sat Apr 12, 2003 4:44 pm

Great. A pissing contest. Forget about the math. Just call Whelen and Tomar and ask them what size wire they recommend for remote heads.