A tiny nick, a big fault
An installer strips the outer skin off a cable with a blunt knife. The blade cuts the thin wire inside by a hair. The cable still works on test day.
Three months later it fails. The right tool strips the cable, and not the wire. Each job in cabling has a tool made for it.
Key words
| Word | What it means |
|---|---|
| Terminate | fit a plug, socket or block to the end of a cable |
| Crimper | a tool that squeezes a plug onto a cable |
| Stripper | a tool that removes the outer layer without cutting inside |
| Punch-down tool | a tool that pushes a wire into a block and trims the end |
| IDC | insulation displacement connector: a slot that cuts through the wire skin by itself |
| Fusion splicer | a machine that joins two fibres with a tiny electric arc |
| Cleave tool | a tool that breaks a fibre end flat and clean |
| Fibre | a thin strand of glass that carries light |
| Cladding | the glass layer round the core that keeps light inside |
The cells students fill in are left blank in this preview.
By the end of this lesson
Note
I can name the tools that terminate cable, say what each does, and put a fibre splice in order.
Starter: test tools
Have a go
Starter: test tools
3 questionsYour answers are marked here and are not kept. A college account keeps every student’s marks.
Copper terminating tools
| Tool | What it does | Take care |
|---|---|---|
| Copper cable stripper | Removes the outer jacket in one turn | Set the blade so the pairs are not cut |
| Cable cutters | Cuts cable and trims wire ends square | Cut flat. Keep fingers clear |
| Crimper | Squeezes an RJ-45 plug onto the wires | Use the right die for the plug |
| Punch-down tool | Pushes each wire into a block and trims it | Blade faces the waste end |
| Screwdrivers | Tighten screw terminals and open cases | Use the right size and an insulated handle |
The cells students fill in are left blank in this preview.
How a punch-down works
A punch-down block has small slots with sharp metal. The slot is an IDC. When you push a wire in, the metal cuts through the skin and grips the copper. You do not strip each wire first.
The punch-down tool pushes the wire all the way in and cuts off the spare end in one move.
Fibre terminating tools
| Tool | What it does | Take care |
|---|---|---|
| Fibre optic stripper | Removes the coating from the glass | Slow and straight. Glass breaks easily |
| Cleaning tools | Alcohol wipes and click cleaners remove dust and oil | Clean before every join |
| Indirect viewing aid | A viewer that lets you see a fibre end without looking into it | Use it only with the light source off |
| Cleave tool | Breaks the fibre flat and square | Put the tiny off-cut in a sharps bin |
| Fusion splicer | Lines up two fibres and joins them with an arc | Follow the maker's guide and wear eye protection |
The cells students fill in are left blank in this preview.
The order of a fusion splice
The steps always go in the same order, because a dirty or crooked end cannot be fixed later.
Slide a protective sleeve on first. Strip, clean, cleave, then load the fibres in the splicer. It lines them up and fuses them. Heat the sleeve over the join and check the result.