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Cable SPIKING... or “shooting cables” as one of my old instructors used to say. What is it? Why do we do it? How do we do it? [THREAD]
![Cable SPIKING... or “shooting cables” as one of my old instructors used to say. What is it? Why do we do it? How do we do it? [THREAD]](https://pbs.twimg.com/media/EmsRSL7XEAI9Mho.jpg "Cable SPIKING... or “shooting cables” as one of my old instructors used to say. What is it? Why do we do it? How do we do it? [THREAD]")
Once upon a time I worked in an airport and one day I took these through security to the airfield. They raised a few eyebrows with the search team I can tell you 
They are bullets from a cable spiking gun [1/12]
![Once upon a time I worked in an airport and one day I took these through security to the airfield. They raised a few eyebrows with the search team I can tell you They are bullets from a cable spiking gun [1/12]](https://pbs.twimg.com/media/EmsXGZ9XcAAnHzZ.jpg "Once upon a time I worked in an airport and one day I took these through security to the airfield. They raised a few eyebrows with the search team I can tell you They are bullets from a cable spiking gun [1/12]")
They are bullets from a cable spiking gun [1/12]
Back in 1889, the Board of Trade demanded PROOF that high voltage buried cables were “safe.” Ferranti had G A Henty hammer a chisel through a LIVE 10kV cable. The guys never felt a thing [2/12]
![Back in 1889, the Board of Trade demanded PROOF that high voltage buried cables were “safe.” Ferranti had G A Henty hammer a chisel through a LIVE 10kV cable. The guys never felt a thing [2/12]](https://pbs.twimg.com/media/EmsXG5JW8AIv483.jpg "Back in 1889, the Board of Trade demanded PROOF that high voltage buried cables were “safe.” Ferranti had G A Henty hammer a chisel through a LIVE 10kV cable. The guys never felt a thing [2/12]")
This was the first recorded practice of “spiking” a cable. The Ferranti tubular main is concentric with an earthed neutral conductor and an iron sleeve, also effectively earthy. The chisel was in contact with the earthed outer as it drove through the insulation 
[3/12]
![This was the first recorded practice of “spiking” a cable. The Ferranti tubular main is concentric with an earthed neutral conductor and an iron sleeve, also effectively earthy. The chisel was in contact with the earthed outer as it drove through the insulation [3/12]](https://pbs.twimg.com/media/EmsXHYvW4AAe2a_.jpg "This was the first recorded practice of “spiking” a cable. The Ferranti tubular main is concentric with an earthed neutral conductor and an iron sleeve, also effectively earthy. The chisel was in contact with the earthed outer as it drove through the insulation [3/12]")
[3/12]
This put a hard short circuit between phase and earth (linked out LIVE and NEUTRAL) and contemporary historians wrote of “the current being rapidly cut off”. This can only have been via FUSE action as no automatic circuit-breakers existed at that time [4/12]
![This put a hard short circuit between phase and earth (linked out LIVE and NEUTRAL) and contemporary historians wrote of “the current being rapidly cut off”. This can only have been via FUSE action as no automatic circuit-breakers existed at that time [4/12]](https://pbs.twimg.com/media/EmsXH2VXMAIiaT3.jpg "This put a hard short circuit between phase and earth (linked out LIVE and NEUTRAL) and contemporary historians wrote of “the current being rapidly cut off”. This can only have been via FUSE action as no automatic circuit-breakers existed at that time [4/12]")
The guy holding the bare chisel would have been in contact with the earthed outer and the fault current would have flown through the chisel to the neutral and sleeve, not through the chisel man. Even so I wouldn’t try it myself, not at 10kV [5/12]
![The guy holding the bare chisel would have been in contact with the earthed outer and the fault current would have flown through the chisel to the neutral and sleeve, not through the chisel man. Even so I wouldn’t try it myself, not at 10kV [5/12]](https://pbs.twimg.com/media/EmsXIPTW8AE2fOU.jpg "The guy holding the bare chisel would have been in contact with the earthed outer and the fault current would have flown through the chisel to the neutral and sleeve, not through the chisel man. Even so I wouldn’t try it myself, not at 10kV [5/12]")
![The guy holding the bare chisel would have been in contact with the earthed outer and the fault current would have flown through the chisel to the neutral and sleeve, not through the chisel man. Even so I wouldn’t try it myself, not at 10kV [5/12]](https://pbs.twimg.com/media/EmsXIQEXMAA7N_4.jpg "The guy holding the bare chisel would have been in contact with the earthed outer and the fault current would have flown through the chisel to the neutral and sleeve, not through the chisel man. Even so I wouldn’t try it myself, not at 10kV [5/12]")
[5/12]
That was 130 years ago. Do we spike cables today? If so why? YES we do. And it’s still to “prove” that they are safe. Not for the media but for us to work on them. We need to joint / repair cables, often in a trench full of other cables. We don’t work LIVE on HV cables [6/12]
![That was 130 years ago. Do we spike cables today? If so why? YES we do. And it’s still to “prove” that they are safe. Not for the media but for us to work on them. We need to joint / repair cables, often in a trench full of other cables. We don’t work LIVE on HV cables [6/12]](https://pbs.twimg.com/media/EmsXJjGXUAABQcG.jpg "That was 130 years ago. Do we spike cables today? If so why? YES we do. And it’s still to “prove” that they are safe. Not for the media but for us to work on them. We need to joint / repair cables, often in a trench full of other cables. We don’t work LIVE on HV cables [6/12]")
If we can positively identify an HV cable and it’s proven DEAD (and earthed) then it’s ok to saw through it to undertake work, subject to a permit ofc. If we can’t be 100% certain, we SPIKE it- just like Ferranti did in 1889. Here’s a modern spiking gun [7/12]
![If we can positively identify an HV cable and it’s proven DEAD (and earthed) then it’s ok to saw through it to undertake work, subject to a permit ofc. If we can’t be 100% certain, we SPIKE it- just like Ferranti did in 1889. Here’s a modern spiking gun [7/12]](https://pbs.twimg.com/media/EmsXKO6XYAAdn8Y.jpg "If we can positively identify an HV cable and it’s proven DEAD (and earthed) then it’s ok to saw through it to undertake work, subject to a permit ofc. If we can’t be 100% certain, we SPIKE it- just like Ferranti did in 1889. Here’s a modern spiking gun [7/12]")
The Ackvoke cable spiking gun fires a chisel through the cable using a bullet. We load the bullet. Stand back. Clear the area. Pull a lanyard. And BOOM 
Cable spiked. This is for HV cables ONLY. NEVER spike an known LV cable [8/12]
![The Ackvoke cable spiking gun fires a chisel through the cable using a bullet. We load the bullet. Stand back. Clear the area. Pull a lanyard. And BOOM Cable spiked. This is for HV cables ONLY. NEVER spike an known LV cable [8/12]](https://pbs.twimg.com/media/EmsXMJmXIAAhUGQ.jpg "The Ackvoke cable spiking gun fires a chisel through the cable using a bullet. We load the bullet. Stand back. Clear the area. Pull a lanyard. And BOOM Cable spiked. This is for HV cables ONLY. NEVER spike an known LV cable [8/12]")
Cable spiked. This is for HV cables ONLY. NEVER spike an known LV cable [8/12]
If the cable is alive, the spiking gun puts a short circuit in it and the protection at the substation will respond and cause the circuit to trip in short order. If it’s already dead (we trust) then nothing else happens. We shoot a hole in the cable. Happy days 
[9/12]
![If the cable is alive, the spiking gun puts a short circuit in it and the protection at the substation will respond and cause the circuit to trip in short order. If it’s already dead (we trust) then nothing else happens. We shoot a hole in the cable. Happy days [9/12]](https://pbs.twimg.com/media/EmsXMizXEAEyOd8.jpg "If the cable is alive, the spiking gun puts a short circuit in it and the protection at the substation will respond and cause the circuit to trip in short order. If it’s already dead (we trust) then nothing else happens. We shoot a hole in the cable. Happy days [9/12]")
[9/12]
After that we saw through the cable, adjacent or actually through the spike hole. It’s then safe to joint / repair / divert / decommission. If sawing though an HV cable, we must be SURE it is dead. The spiking gun makes damn sure 
[10/12]
![After that we saw through the cable, adjacent or actually through the spike hole. It’s then safe to joint / repair / divert / decommission. If sawing though an HV cable, we must be SURE it is dead. The spiking gun makes damn sure [10/12]](https://pbs.twimg.com/media/EmsXNFgXcAE87b9.jpg "After that we saw through the cable, adjacent or actually through the spike hole. It’s then safe to joint / repair / divert / decommission. If sawing though an HV cable, we must be SURE it is dead. The spiking gun makes damn sure [10/12]")
[10/12]
There are exceptions. If we can physically trace the point of work to an earth connection, don’t need to spike. Certain sheath repairs don’t need to spike. If positively ID’d at the point of work, don’t need to spike. But I bet that spiking gun has saved COUNTLESS lives [11/12]
I’ve never spiked a live cable (yet) 
abut I’ve met engineers who have. No need to beat yourself up- there’s a good reason we spike! Better weld a spiking gun than cremate a cable jointer eh [12/12] 
![I’ve never spiked a live cable (yet) abut I’ve met engineers who have. No need to beat yourself up- there’s a good reason we spike! Better weld a spiking gun than cremate a cable jointer eh [12/12]](https://pbs.twimg.com/media/EmsXOHtWEAI5iak.jpg "I’ve never spiked a live cable (yet) abut I’ve met engineers who have. No need to beat yourself up- there’s a good reason we spike! Better weld a spiking gun than cremate a cable jointer eh [12/12]")
![I’ve never spiked a live cable (yet) abut I’ve met engineers who have. No need to beat yourself up- there’s a good reason we spike! Better weld a spiking gun than cremate a cable jointer eh [12/12]](https://pbs.twimg.com/media/EmsXOH5WMAAt5kc.jpg "I’ve never spiked a live cable (yet) abut I’ve met engineers who have. No need to beat yourself up- there’s a good reason we spike! Better weld a spiking gun than cremate a cable jointer eh [12/12]")
![I’ve never spiked a live cable (yet) abut I’ve met engineers who have. No need to beat yourself up- there’s a good reason we spike! Better weld a spiking gun than cremate a cable jointer eh [12/12]](https://pbs.twimg.com/media/EmsXOH-XcAAXz21.jpg "I’ve never spiked a live cable (yet) abut I’ve met engineers who have. No need to beat yourself up- there’s a good reason we spike! Better weld a spiking gun than cremate a cable jointer eh [12/12]")
![I’ve never spiked a live cable (yet) abut I’ve met engineers who have. No need to beat yourself up- there’s a good reason we spike! Better weld a spiking gun than cremate a cable jointer eh [12/12]](https://pbs.twimg.com/media/EmsXOIHWEAM3eHL.jpg "I’ve never spiked a live cable (yet) abut I’ve met engineers who have. No need to beat yourself up- there’s a good reason we spike! Better weld a spiking gun than cremate a cable jointer eh [12/12]")
abut I’ve met engineers who have. No need to beat yourself up- there’s a good reason we spike! Better weld a spiking gun than cremate a cable jointer eh [12/12]
