Wire & connectorsRebuild shelfUnplug and unscrew

Mains cord

Also called IEC lead, kettle lead, appliance cord, figure-8.

A cord with a known insulation rating is a mains cord. Ethernet is not. Speaker wire is not. The IEC C13 lead from a PC and the C7 'figure-8' from a radio are the useful, reusable ones, because the appliance end is standardized.

If you are new to this category

Wire and plugs are how power and signals move. The insulation is the safety, not the copper. Ethernet cable is fine for small signals and low voltage. It is not a substitute for a power cord. A connector you can unplug is worth more than a wire you have to solder every time.

Match the plug that came with the brick. Center-positive is common and not universal. The drawing on the label is a map: the dot is the center, the ring is the outside.

Center pin and outside sleeve

The drawing on the brick is the polarity. A dot inside a C-shaped ring means the center is positive when the plus sign points at the dot. Measure anyway. The two common hole sizes, 2.1 mm and 2.5 mm, almost fit each other and that is how the center pin gets bent.

Mains voltage. Line voltage, and the DC bus just after the rectifier, both kill. A disconnected cord is not a discharged supply.

Specification. The right-hand column is what is typical. The label on the part in your hand wins if they disagree.
What to look for	Usual figure
IEC C13	The PC lead. 10 A class. Keep it with the supply.
C7	Unpolarised figure-8. Fine for double-insulated gear that used one.
Hardwired	A kettle or iron cord may be high-flex and heat-resistant. Ordinary lamp cord is not a kettle cord.

Volts are electrical pressure, amps are how much current is flowing, and ohms are how hard the part resists that flow. A higher voltage than the part was built for is how salvage parts die on the bench. If a cell in the table says “read the stamp”, that stamp is the whole specification.

What people actually use it for

Powering a supply that already has the matching inlet
A cord for a rebuilt double-insulated tool, same type as original

Leave this one when

Nicks, tape repairs, or a melted spot. Cord damage is how old appliances start fires. Also skip any plan to use this wire as speaker cable inside a 5 V project and then later as mains again.

Buying a new one is the better idea when

A new cord of the right gauge and temperature rating. Cords are cheaper than the failure.

How to tell if this one still works

Continuity of all conductors including earth, then a visual along the whole length, then a flex at the strain relief.

Tools you will want: Meter.

Words on this page

Short meanings, so the rest of the entry is readable if you are not already doing this every weekend.

mains: Ordinary household wall power. It can kill. Unplug before you open anything that used it, and do not experiment on live wiring.
continuity: A meter mode that beeps when two points are connected. It is how you map a switch: beep, then click, then see if the beep changes.

Where people actually find it

9 notes, most useful first. “Leave it” means the part is in that machine and you should not take it: it is dangerous, worn out, or only useful if you already know that exact repair.

Harvest at a glance
From	Call	How many	How often	Where it sits
Power strip	Prize	1	usually	The lead.
Desktop PC	Worth it	1	always	IEC lead.
Microwave oven	Worth it	1	always	Rear.
Electric kettle	Worth it	1	always	Base.
Blender	Worth it	1	always	Rear.
Paper shredder	Worth it	1	always	Rear.
Clock radio or stereo	Worth it	1	always	Rear.
Uninterruptible power supply	Worth it	1	always	Input.
Hair dryer	Bonus	1	always	Handle.

Prize — take this firstPower strip1 · usually
In this particular machine
A real cord, if the jacket is intact.
Where to look
The lead.
How to get it out
Inspect every centimetre.
The condition to expect
Nicks are a reject.
Worth pullingDesktop PC1 · always
In this particular machine
C13, usually 10 A class.
Where to look
IEC lead.
How to get it out
Keep it with the supply.
The condition to expect
Nicks and tape are a reject.
Worth pullingMicrowave oven1 · always
In this particular machine
A proper appliance cord.
Where to look
Rear.
How to get it out
Inspect the grommet.
The condition to expect
Good if not cracked.
Worth pullingElectric kettle1 · always
In this particular machine
Often a high-flex cord. Inspect it.
Where to look
Base.
How to get it out
The connector in the base is not a universal jack.
The condition to expect
Flex cracks at the entrance.
Worth pullingBlender1 · always
In this particular machine
Ordinary appliance cord.
Where to look
Rear.
How to get it out
Inspect.
The condition to expect
Good.
Worth pullingPaper shredder1 · always
In this particular machine
Ordinary.
Where to look
Rear.
How to get it out
Inspect.
The condition to expect
Good.
Worth pullingClock radio or stereo1 · always
In this particular machine
Inspect the strain relief.
Where to look
Rear.
How to get it out
Old PVC cracks.
The condition to expect
Inspect.
Worth pullingUninterruptible power supply1 · always
In this particular machine
IEC or fixed.
Where to look
Input.
How to get it out
Inspect.
The condition to expect
Good.
Bonus, if you are already in thereHair dryer1 · always
In this particular machine
Flexes until it breaks at the strain relief. That may be the fault.
Where to look
Handle.
How to get it out
Inspect.
The condition to expect
Often tired.