How long is Section C of the AM2?

A maximum of 30 minutes, with 5 minutes to read and prepare first. NET gives the same time on the AM2, the AM2S and the AM2S v1.

What is the safe isolation procedure for the AM2?

NET’s procedure: identify the point of isolation; inform the customer; operate the isolator, lock off and fit a warning notice; select approved test equipment and prove it works; test all combinations on the outgoing side of the isolator; re-prove the test equipment.

What is the 10-point test?

On a three-phase and neutral supply, the ten combinations: L1–L2, L1–L3, L1–N, L1–E, L2–L3, L2–N, L2–E, L3–N, L3–E and N–E, all tested on the outgoing side of the isolator.

Can I turn the whole board off to be safe?

Not for tasks 1 and 2. NET says all other circuits must remain energised, and lists turning off other circuits as a common error. Task 3 is isolating the distribution board in your fault diagnosis bay.

Why does safe isolation catch so many candidates?

It has no margin for error. When NET reviewed the first results of the 2010 AM2, not carrying out safe isolation to recognised practice was the most common cause of failure. Practise the procedure until it is automatic, with someone watching, as NET suggests.

AM2 SECTION C

AM2 Section C: AM2 Section C — Safe Isolation — 30 minutes, three tasks

Section C of the AM2 is 30 minutes, with 5 minutes to read and prepare first, on every version (AM2, AM2S and AM2S v1). You isolate safely for three tasks: replacing a single-phase item, replacing a three-phase item, and isolating the distribution board in your fault diagnosis bay. For the first two, every other circuit stays on.

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8 min readUpdated 2026-11-03Andrew Moore, Founder of Elec-Mate

Written and reviewed by Andrew Moore, founder of Elec-Mate, against BS 7671:2018+A4:2026, IET Guidance Note 3 and the IET On-Site Guide.

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Key takeaways

01Section C: a maximum of 30 minutes plus 5 minutes’ reading, on the AM2, AM2S and AM2S v1 (NET).
02Three tasks: a single-phase item, a three-phase item (all other circuits staying on), then the distribution board in your fault diagnosis bay.
03NET’s procedure: identify, inform, isolate and lock off with a warning notice, prove the tester, test all combinations on the outgoing side, re-prove the tester.
04On a TP&N supply the 10-point test is L1–L2, L1–L3, L1–N, L1–E, L2–L3, L2–N, L2–E, L3–N, L3–E and N–E.
05NET’s Top Tips video: miss a combination, or leave the key unsecured, and you will fail.
06Only isolate the circuit you are working on, and check whether an item is isolated or just switched off.

01 · AM2 Section C

What Section C covers

Section C is the second safe isolation in the AM2 (the first opens Section A1). NET sets three tasks, fully observed by the assessor: isolate so a single-phase item of equipment can be replaced, isolate so a three-phase item can be replaced, and isolate the distribution board in your fault diagnosis bay. For tasks 1 and 2, all other circuits must remain energised. The maximum time is 30 minutes, with 5 minutes to read and prepare, on all three versions of the AM2 NET runs for installation and maintenance electricians.

New-style bay, 2026

NET’s new AM2 bay (in all centres by the end of August 2026) brings safe isolation that considers other sources, such as solar PV and battery storage. NET’s AM2S v1 checklist asks for safe isolation “taking any secondary supplies into account”. Anything not part of your version is locked off by the assessor.

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02 · AM2 Section C

NET’s safe isolation procedure

Identify your point of isolation.
Inform the customer that you will be isolating the supply.
Operate the isolator, lock off and fit a warning notice.
Select approved test equipment and prove that it is working.
Test on the outgoing side of the isolator, all combinations.
Re-prove your test equipment is working.

That is NET’s own list from its Pre-Assessment Manual. Keep the lock-off key with you throughout.

03 · AM2 Section C

The 10-point test on a TP&N supply

L1 and L2
L1 and L3
L1 and neutral
L1 and earth
L2 and L3
L2 and neutral
L2 and earth
L3 and neutral
L3 and earth
Neutral and earth

All ten are tested on the outgoing side of the isolator you have locked off. A single-phase supply has three combinations: line–neutral, line–earth and neutral–earth.

04 · AM2 Section C

NET’s common errors in safe isolation

Not testing all the combinations (the 10-point test).
Testing at the wrong position on the switch.
Not proving the test equipment before and after.
Not keeping the key in a secure place.
Not fitting warning notices.
Turning off other circuits: only isolate the circuit you are going to work on.
Not checking switches on the circuit: is the item isolated, or just switched off?

NET keeps its marking criteria confidential, but it is clear that safe isolation has no margin for error. Its Top Tips video says that if you do not test all combinations, or the key is not kept secure, you will fail.

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05 · AM2 Section C

Kit on the day

The centre supplies the safe isolation kit, the test equipment and every other tool. NET’s video says you will see the kits before you start and have time to familiarise yourself with them. The only tools of your own you may use are insulated side cutters, wire strippers and pliers, if they are safe and serviceable.

06 · AM2 Section C

Study with Elec-Mate

Elec-Mate’s AM2 course follows the AM2S v1 section by section, with the differences for the AM2 and original AM2S, plus a safe isolation simulator, a mock AM2 day and a 24-decision walk-through of the whole assessment. Not affiliated with or endorsed by NET.

Test yourselfTry the free AM2 mock examTimed, marked instantly, with an explanation on every question. No sign-up.

AM2 Section C — FAQ

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