228Insulation resistance of underground consumer's mains

228 Insulation resistance of underground consumer's mains

(1) Before consumer's mains are first placed into service or use, the insulation resistance—

(a) between the conductors of underground consumer's mains; and

(b) between the conductors of underground consumer's mains and earth; and

(c) if the consumer's mains conductors are surrounded by a metallic sheath, between the conductors of underground consumer's mains and the metallic sheath—

must not be less than the relevant minimum insulation resistance specified in column 2 of Table 228 when tested with a 500V d.c. insulation resistance tester.

(2) When existing underground consumer's mains are reconnected to electricity supply, the insulation resistance—

(a) between the conductors of underground consumer's mains; and

(b) between the conductors of underground consumer's mains and earth; and

(c) if the consumer's mains conductors are surrounded by a metallic sheath, between the conductors of underground consumer's mains and the metallic sheath—

must not be less than one megohm when tested with a 500V d.c. insulation resistance tester.

Table 228—Minimum insulation resistance of underground consumer's mains

• Column 1**Route length of underground consumer's mains Column 2**Minimum insulation resistance
• A ≤ 50 m 50 megohms
• B > 50 m and ≤ 75 m 45 megohms
• C > 75 m and ≤ 100 m 40 megohms
• D > 100 m and ≤ 125 m 35 megohms
• E > 125 m and ≤ 150 m 30 megohms
• F > 150 m and ≤ 175 m 25 megohms
• G > 175 m and ≤ 200 m 20 megohms
• H > 200 m and ≤ 225 m 15 megohms
• I > 225 m and ≤ 250 m 10 megohms
• J > 250 m 5 megohms