The red wire. No, the Blue!

Just watching Frank Drebin disarm a small nuke in Naked Gun 2 1/2, got me wondering about a common TV and movie trope.

In disarming a bomb, why can’t you just yank out the detonator from the C4 explosive, cut the red and/or blue wires feeding electrical charges or do something else to sever the explosive from the detonator or the trigger button. Yes I realise they may be booby-trapped, but if there is no evidence of that, can it be done?

Do we really need to sit through two commercial breaks to get to three seconds before detonation to sort everything out?

I assume there is a factual answer, but if it goes into Cafe Society because of the content, that’s okay.

If you’re certain that’s how the bomba was constructed, then pulling the cap out of the putty is the right answer. But if there is a hint of evil genius in the bomb maker, the cap you see is redundant or a decoy, or wired into a dead-man switch, etc. My preferred method is to fully encase the timer and cap within the C4, and then create a complex theater of wires, caps, and pornographic drawings all around the brick to keep the nosey do-gooder busy while my plan unfolds.

Ha!, and once again, Ha!

In the real world, bomb wires are rarely color-coded, and usually pulling the wire off of the detonator makes it so the bomb won’t go kaboom.

For a well-known example, the FBI reconstructed one of Ted Kaczynski’s bombs. There is a picture of the reconstruction on Ted’s wikipedia page:

It is VERY simple compared to a Hollywood bomb, and very easily disarmed if you can get the box open without setting it off.

“Disconnect the easily accessible alligator clip” wouldn’t be as dramatic for Hollywood, so even though it would be very effective on the above bomb, it wouldn’t make for a good TV/Movie scene.

In WWII, the Germans found out (through spies) that unexploded bombs also worked well as terror weapons, and started putting booby traps and all sorts of things in their bombs to prevent them from being easily disarmed. This is one of the few cases where real-life bombs had anything even coming close to a Hollywood bomb. In those old German bombs, they did come up with techniques for disarming them that did involve things like “cut the blue wire”, though these techniques were bomb model specific. The bombs often had fake wires designed to look like they went to the detonator when in reality cutting the fake wires would trigger the bomb to explode. The real detonator wires would be hidden underneath. Once you had some way of identifying the real detonator wires, the bomb disposal technician would cut those wires instead.

Real-world bombs rarely contain booby traps and are usually crude and simple in design.

Real bomb squads prefer a technique of “cut everything at once”, by using their own explosives to trigger a controlled detonation. After, of course, evacuating the vicinity, in case the detonation ends up being not so controlled.

You may remember this one:

Some real bombs are not so easily disarmed.

Dog Fort covers the situation, second cartoon:


I think this may be a good time to mention one of my favourite historical figures - Charles Howard, 20th Earl of Suffolk.

That’s an awesome story! I especially liked this line:

“The room became absolutely silent apart from the schmaltzy piped-in music, which the bomb squad had been unable to disarm despite heroic efforts.”


I was impressed that they included “vomitoria” and used it correctly. Actually the first time I’ve seen it used correctly.

Real world bombs also rarely have countdown displays. But pretty much every TV or movie bomb does.

**The red wire. No, the Blue! **

Cut the tiny bit blue one.

As others have mentioned, removing the detonator is a good way to disarm the bomb (assuming it is not booby-trapped). The C4 itself is a rather “stable” substance in the sense that it can survive being beaten up, lit on fire, shot with bullets, etc… But only another explosive is likely to make it detonate. IRL, bomb-makers will commonly set their bombs in “stages” where a small and easily-initiated explosive (eg, the blasting cap) will set off a more stable explosive. The actual “bulk” explosive is usually the most stable material and can require one or more stages of less-stable explosives to detonate.

I’d also submit that Frank has the right idea, here. If a nuclear bomb is about to detonate, you might as well just start ripping out random wires. Nuclear bombs need a very precise explosion to create the desired “kaboom.” An imperfect explosion might still kill you, but at least you would prevent the nuclear chain reaction.

…I don’t see that Frank has any ideas, here. Did you mean to refer to some other poster?

IIRC, all Drebin did was start to run and trip over the cord, pulling out the plug and shutting down the bomb.

The “random wires” solution was the one they should have used in “The Peacemaker.”

Start with the simple bomb… a timer controls applying power to the blasting cap embedded in the C4 or fertilizer-diesel mixture or whatever.
Pull the cap out, the major explosive does not receive an immediate enough powerful shock, does not explode.

So what are you as a bomb-maker going to do to prevent this?
Hiding the bomb is a good start.
IIRC the Mad Bomber in Boston, if I remember long ago articles, used a mercury switch to detect if the bomb was being moved - once armed, jarring or tilting the bomb could close the circuit using a tiny glass vial with a blob of mercury and two wires in it. Nowadays, there are electronic gizmos t detect movement, but same idea.

But then, the bomb has to avoid vibration after being armed (powered on). Those Speed movies where the bomb can be shaken around by hitting LA potholes at 60MPH but you still can’t pick it up - pure pig leavings.
Then of course, build a dam around the bomb (Clay?) and pour in liquid nitrogen. That should freeze any mercury fuses, and as a bonus kill any battery.
So, you Mr. Bombmaker add a temperature switch to the bomb. Too cold, it burns up.
Put a switch on the lid, if the bomb box is opened, boom. A simple variation on tripwire, weight sensitive switch under carpet, etc.
Pull the blasting cap out? Make a fake blasting cap that is actually a spring-loaded switch - pull it out, the circuit closes, mission accomplished. So if the bomb has 2 blasting caps, is that insurance or a trick? But, how good are your mimicry skills in making fake blasting caps? Instead of pulling it out, slowly peel back the C4?
Does the wiring sense when a wire has been cut? does the wiring sense changes to capacitance as the wires are handled or the insulation is cut and the wire clippers are about to do their thing? Dual ignitions that will trigger if their buddy goes offline, to prevent tampering You better have a pretty sophisticated bombmaker who knows real fancy electronics…

Plus, there’s the Rube Goldberg principle - the more complex the device, the better the odds it won’t work. Remember in the second wave of Tube bombings in London (and the underwear bomber), the terrorists could not even make explosive that went “bang” instead of “fizz”. Hooking a cellphone to a blasting cap trigger seems to be the limit of modern tech tricks. (Leading to the result that when they tried to blow up the president of Pakistan over 10 years ago, the bridge blew up a minute after his car went over it - presumably the trigger text arrived after his jammers were out of range…)

But basically, your typical bomb is built ot meet the needs it expects to encounter. How tamper-proof and analysis proof does it have to be?

And ”it always stops at ‘1’ on the show.”

There are electromechanical ordnance triggering devices in nuclear weapons that have to be disassembled in a certain sequence lest a failsafe render the device unusable, but they don’t just blow up if you accidentally go out of sequence for obvious reasons. Some of the earliest atomic weapons had to be assembled while in the aircraft, and an static electric discharge or damage during assembly could potentially cause an unintended criticality event, but that wasn’t an intentional design choice; it was a reflection of the crude state of protective safety interlocks and safe design in nuclear weapons at that time.

The notion of complex explosive devices with multiple protective systems and “collapsing circuits” which detect the severance of a primary firing circuit and initiate a secondary firing circuit are about as much of a trope as the sophisticated psychopath who creates an elaborate puzzle for investigators using his victims to leave a steganophic message on a map of their locations, or the renegade police detective who gets to run around in an improbable undercover disguise with an unlimited clothing budget, driving Italian supercars, and getting into weekly gunfights. In theory, a technically proficient bomber could do such a thing; in reality, most bombers put their effort into not allowing the device to be discovered before it detonates in the first place.


Frank is the name of the character in the segment.

He pulls out a few fistfuls of wires before he trips over the cord.

Thanks all - that’s really helpful stuff.

But what if, in Rocky VIII he finishes the climactic fight against his mortal enemy and then goes into the dressing room and There’s The BOMB the enemy had planted because deep down he knew that Rocky would win, and Rocky’s still got his boxing gloves on!!?!? I think that would add some dramatic tension and nuance sadly missing in the previous three or four movies in the franchise.

Plus Rocky had the colour cones knocked out of his eyes with a sneaky punch, so can’t distinguish wire colours.

As I recall, one of the most effective ‘disarming’ techniques used by the British was to drill a hole in the bomb casing and steam out all of the explosive. Then if it was triggered, only the blasting cap would explode, with little or no damage to the area. But the trick was to complete this process before the bomb timer ran out, or the vibration was enough to set off the detonator.

And I remember reading a case where the Rube Goldberg principle that md2000 mentions intervened:
Terrorists planned to plant a bomb in a public place in Israel. Their bomb-maker had assembled it, had carefully disguised it, set the timer going, and delivered it to those who were to plant it. But they were on their way to sneak it into place when the bomb went off.

Seems that the bomb maker was a fanatic who refused to recognize ‘Jew time’ (because the Israel government had approved using Daylight Saving Time) so he set his timer on ‘Arab time’, and it went off an hour earlier than the bomb planters had expected.