Part 6: Inspection and Testing - What You Need to Know

Overview of Part 6

Part 6 of BS 7671 deals with the inspection and testing of electrical installations. Although it has fewer questions (28 in our question bank), it’s critically important for both the exam and real-world practice.

 

Exam weight: Part 6 accounts for approximately 4 out of 60 questions (7% of the exam). Despite the lower question count, the testing sequence and insulation resistance values are among the most frequently examined topics in the entire paper.

 

Key Concepts

Initial Verification (Chapter 61)

Before an installation is put into service, it must undergo initial verification comprising:

• Visual inspection: Checking for compliance without instruments
• Testing: Using appropriate test instruments to verify safety

Inspection Requirements (Section 611)

Visual inspection should confirm:

 

Requirement	What to Check
Connection of conductors	All conductors correctly terminated and secure
Conductor sizing	Adequate for the circuit’s design current
Fire barriers and seals	Present and intact where required
Labelling and identification	All circuits and devices properly marked
Accessibility	Equipment accessible for maintenance

 

Testing Sequence (Section 612)

Tests must be carried out in a specific order:

 

Step	Test	Purpose
1	Continuity of protective conductors	Confirms CPCs are intact (dead test)
2	Continuity of ring final circuit conductors	Confirms ring is not broken (dead test)
3	Insulation resistance	Verifies insulation integrity — 500V DC, min 1.0 MΩ (dead test)
4	Polarity	Confirms L and N are correctly connected (dead test)
5	Earth fault loop impedance	Compares Zs against Table 41.3 values (live test)
6	RCD operation	Verifies trip time and current (live test)

 

Key principle: Dead tests always come before live tests. You don’t energise the circuit until you’ve confirmed it’s sound.

 

Periodic Inspection (Chapter 62)

Existing installations require periodic inspection to determine:

• Safety for continued use
• Any deterioration or damage
• Changes that may have occurred since last inspection

Common Exam Questions

Part 6 questions often focus on:

 

Topic	What to Know
Correct sequence of tests	Dead tests first, then live tests — order matters because each test depends on the previous result
Minimum insulation resistance values	500V DC test voltage with a minimum reading of 1.0 MΩ
When periodic inspection is required	Determined by installation type, environment, and previous condition
Documentation requirements	New work = EIC, minor additions = MEIWC, periodic inspection = EICR

 

Practice Part 6 Questions

Test your knowledge with our Part 6 practice quiz containing 28 focused questions on inspection and testing procedures.

 

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