What's in a safe isolation kit, and do you need one?

Safe isolation is how electricians make sure a circuit is dead, and stays dead, before they touch it. The kit is the set of tools that makes that possible.

This is a buying guide, not training. It explains what the equipment is. It does not teach you how to isolate a circuit. Learn the procedure from your college and employer, and follow it every time.

What's in the kit

• A two-pole voltage tester. This is what you use to prove a circuit is dead. It should meet HSE guidance note GS38, which covers things like shrouded probes and limited exposed tip length.
• A proving unit. A small device that puts out a known voltage, so you can check your tester works immediately before and after you use it. A tester you haven't proved tells you nothing.
• Lock-off devices. Clips and clamps that physically stop a breaker or isolator being switched back on.
• A padlock. One lock, one key, and the key stays with you.
• Warning tags or labels. So anyone who finds the lock knows why it's there and who to speak to.

Why not a multimeter or a volt stick?

A multimeter can be on the wrong range, have a blown fuse or a flat battery, and show nothing on a live circuit. Non-contact "volt stick" detectors are useful for a quick check but can miss live conductors. Neither should be relied on to prove dead.

Buying a kit or buying separately

A kit gives you everything matched and in one case, which makes it more likely you'll actually carry all of it. Buying a tester on its own costs less up front and suits a first-year who is always working alongside someone qualified.

What to check before you buy

• The tester is a two-pole type and states compliance with GS38.
• The category rating (CAT III or CAT IV) suits the installations you work on.
• The proving unit is compatible with the tester.
• It comes from a known brand through a proper retailer. This is not the thing to buy from an unknown marketplace seller.

Many employers supply this equipment, so ask before you spend. Our first-year guide covers what else you need.