Class of Circuits involved at upper level

Other facilities at lower level at crossing, conflicts or on poles jointly used

Grade of construction to be used at upper level

H

Major Class C Circuits

"A"

H or L

Major railways (steam, electric or other motive power at crossing only)

"A"

H or L

Minor railways (at crossing only)

"B"

H

Under all conditions not required to be grade “A” except supply cables treated as specified in Rule 57.8

"B"

L

Under all conditions not required to be Grade “A” or “B”

"C"

Supply cables treated as specified in Rule 57.8

Under all conditions

"C"

Major Class C

Class H circuits

"A"

Minor Class C

Class H circuits

"B"

C

Major railways (at crossing only)

"B"

C

Class L circuits of more than 750 volts

"C"

C

Supply cables treated as specified in Rule 57.8

"F"

C

Under all conditions not required to Grade “A,” “B,” or “C”

"F"