Table 4

Minimum Safety Factors

Element of Line

Grade of Construction

Grade “A”

Grade “B”

Grade “C”

Grade “F”

Conductors, splices and conductor fastenings (other than tie wires)

2

2

2

1

Pins

2

2

1

1

Pole line hardware

  2

  2

2

2

Line insulators (mechanical)

3

2

2

2

Guy Insulators (mechanical)

Interlocking

  2

2

2

2

Noninterlocking

  3

3

3

--

Guys, except in light loading districts rural districts

2

2

2

1 ½

Guys, in light loading rural districts

2

1 ½

1 ½

1 ½

Messengers and span wires

2

2

2

2

Wood poles

4

3

2

1

Structural or tubular steel poles, towers, crossarms and steel members of foundations

1 ½

1 ½

1 ½

--

Foundations against uplift

1 ½

1 ½

1 ½

--

Foundations against depression

3

2

2

--

Reinforced concrete poles

4

3

3

--

Crossarms (wood)

2

2

2

1