DesNo09-08-029, GO 95 - Rule 37, Table 1

Original Version

Rule 37, Table 1

Table 1

Basic Minimum Allowable Vertical Clearance of Wire Above Railroads, Thoroughfares , Ground or Water Surface; Also clearances from Poles, Buildings, Structures or Other Objects(nn)

(Letter References Denote Modifications of Minimum Clearances as Referred to in Note Following this Table)

Case No	Nature of Clearance	Wire or Conductor Concerned
Case No	Nature of Clearance	A Span wires other than trolley span wires), overhead guys and messengers	B Communication conductors (including open wire, cables and service drops), supply service drops of 0-750 volts	C Trolley Contact, feeder and span wires 0-5000 volts	D Supply conductors of 0-750 volts and supply cables treated as in Rule 57.8	E Supply Conductors and supply cables, 750-22,500 volts	F Supply Conductors and supply cables 22.5 – 300 kV	G (mm)Supply Conductors and supply cables more 300 - 550 kV
1	Crossing above tracks of railroads which transport or propose to transport freight cars (max height 15 ft 1in) where not operated by overhead contact wires (a) (b) (c) (d)	25 ft	25 ft	22 ft	25 ft	28 ft	34 ft	34 ft
2	Crossing or paralleling above tracks of railroads operated by overhead trolleys (b) (c) (d)	26 ft (e)	26 ft (e) (f) (g)	22.5 Feet (h) (i) (eee)	27 ft (e) (g)	30 ft (g)	34 ft (g)	34 ft (g) (kk)
3	Crossing or along thoroughfares in Urban districts or crossings thoroughfares in rural districts (c) (d)	18 ft (j) (k) (ii)	18 ft (j) (l) (m) (ii) (aa)	19 ft (hh) (eee)	20 ft (ii)	25 ft (o) (ii)	30 ft (o) (ii)	30 ft (o) (ii) (kk)
4	Above ground along thoroughfares in rural districts or across other areas capable of being transversed by vehicles or agricultural equipment.	15 ft (k)	15 ft (m) (n) (p)	19 ft(eee)	19ft	25 ft(o)	30 ft (o) (p)	30 ft. (o) (kk)
5	Vertical ground in areas accessible to pedestrians only.	8 ft	10 ft (m) (q)	19 ft(eee)	12 ft	17 ft	25 ft (o)	25 ft. (o) (kk)
6	Vertical clearance above buildings and bridges (or other structures which do not ordinarily support conductors and on which men can walk) whether attached or unattached.	8 ft (r)	8 ft (r)	8 ft	8 ft	12 ft	12 ft	20 ft (ll)
6a	Vertical clearance above non-walkable surfaces on buildings, bridges or other structures which do not ordinarily support conductors except generating plants or substations wheather attached or unattached	2 ft	8 ft (yy)	8 ft	8 ft (zz)	8 ft	8 ft	20 ft
7	Horizontal clearance of conductor from buildings (except generating and substations), bridges or other structures (upon which men may work) where such conductor is not attached thereto. (a) (t)	--------------	3 ft (u)	3 ft	3 ft (u) (v)	6 ft (v)	6 ft (v)	15 ft (v)
8	Distance of conductor from center line of pole, wheter attached or unattached (w) (x) (y)	--------------	15 in (a) (aa)	15 in (aa) (bb) (cc)	15 in (aa) (o) (dd)	15 or 18 in (o) (dd) (ee) (jj)	18 in (dd) (ee) (jj)	Not Applicable
9	Distance of conductor from surface of pole, crossarm or other overhead line structure upon which it is supported, providing it complies with Case 8 above (x) (ee)	--------------	3 in (aa) (ff)	3 in (aa) (cc) (gg)	3 in (aa) (dd) (gg)	3 in (dd) (gg)	¼ pin spacing shown in Table 2 Case 15 (dd)	½ pin spacing shown in Table 2 Case 15 (dd)
10	Radial centerline clearance of conductor or cable (unattached) from non-climbable street lighting or traffic signal poles or standards, including mastarms, brackets and lighting fixtures , and from antennas that are not part of the overhead line system.	-------------	1 ft (oo) (u) (rr) (ss)	15 in. (bb) (cc	3 ft (oo)	6 ft (pp)	10 ft (qq)	10 ft (ll)
11	Water areas not suitable for sailboating (tt) (uu) (ww) (xx)	15 ft	15 ft		15 ft	17 ft	25 ft	25 ft (kk)
12	Water areas suitable for sailboating, surface area of: (tt) (vv) (ww) (xx) (a) Less Than 20 acrea (b) 20 to 200 acres (c) Over 200 to 2,000 acres (d) Over 2,000 acres	18 ft 26 ft 32 ft 38 ft	18 ft 26 ft 32 ft 38 ft	--- --- --- ---	18 ft 26 ft 32 ft 38 ft	20 ft 28 ft 34 ft 40 ft	27 ft 35 ft 41 ft 47 ft	27 ft (kk) 35 ft (kk) 41 ft (kk) 47 ft (kk)
13	Radial clearance of bare line conductors from tree branches or foliage. (aaa) (ddd)			18 in. (bbb)		18 in. (bbb)	¼ pin spacing show in Table 2, case 15 (bbb) (ccc)	½ pin spacing show in Table 2, case 15

References to Rules Modifying Minimum Clearances in Table 1

(a) Shall not be reduced more than 5% because of temperature or loading 37

1. Supply Lines 54.4-B1
2. Communication Lines 84.4-B1

(b)   Shall be increased for supply conductors on Suspension insulators, under certain conditions   37

(c)   Special clearances are provided for traffic signal equipment   58.4-C

(d)   Special clearances are provided for street lighting equipment   58.5-B

(e)   Based on trolley pole throw of 26 feet. May be reduced where suitably protected.

1. Supply Guys     56.4-B2
2. Supply cables and messengers 57.4-B2
3. Communication Guys     86.4-B2
4. Communication cables and messengers   87.4-B2

(f) May be reduced depending on height of trolley contact conductors.

1. Supply Service Drop 54.8-C5
2. Communication service drops 84.8-D5

(g) May be reduced and shall be increased depending on trolley throw

1. Supply conductors (except service drops) 54.4-B2
2. Communication conductors (except service drops) 84.4-B2

(h) May be decreased where freight cars are not transported.

1. Trolley contact and feeder conductors 74.4-B1
2. Trolley span wires 77.4-A

(i) May be reduced for trolley contact and span wires in subways, tunnels and under bridges and in fenced areas.

1. Trolley contact conductors 74.4-E
2. Trolley span wires 77.4-A

(j) May be reduced at crossings over private thoroughfares and entrances to private property and over private property.

1. Supply Service drops    54.8-B2
2. Supply Guys     56.4-A
3. Communication service drops    84.8-C2
4. Communication guys    86.4-A

(k) May be reduced along thoroughfares where not normally accessible to vehicles.

1. Supply Guys 56.4-A1
2. Communication Guys 86.4-A1

(l) May be reduced where within 12 feet of curb line of public thoroughfares

1. Supply Service drops 54.8-B1
2. Communication service drops 84.8-C1

(m) May be reduced for railways signal cables under special conditions 84.4-A4

(n) May be reduced in rural districts

1. Intentionally Left Blank
2. Intentionally Left Blank
3. Communication conductors along roads 84.4-A2

(o) May be reduced for transformer, regulator or capacitor leads.

1. Transformer Leads 58.1-B
2. Regulator or Capacitor Leads 58.1-B

(p) May be reduced across arid or mountainous areas

1. Supply Conductors of more than 22,500 Volts 54.4-A1
2. Communication conductors 84.4-A1

(q) Shall be increased or may be reduced under special conditions.

1. Increased for supply service drops on industrial or commercial premises    54.8-B3a
2. Supply service drops on residential premises     54.8-B3b
3. Communication conductors     84.4-A3
4. Increased for Communication service drops on industrial or commercial premises    84.8-C3a
5. Communication service drops on residential premises   84.8-C3b

(r) May be reduced above roofs of buildings under special conditions

1. Supply overhead guys     56.4-G
2. Supply service drops     54.8-B4
3. Communication overhead guys    86.4-F
4. Communication conductors and cables    84.4-E
5. Communication service drops   84.8-C4

(s) Also applies at fire escapes, etc.

1. Supply Conductors     54.4-H1
2. Supply service drops on industrial or commercial premises     54.8-B4a
3. Supply service drops on residential premises    54.8-B4b
4. Communication Conductor   84.4-E

(t) Special Clearances where attached to buildings, bridges or other structures

1. Supply conductors of 750-21,000 volts     54.4-H2
2. Trolley Contact Conductors     74.4-E
3. Communication Conductors   84.4-F

(u) Reduced clearances permitted under special conditions

1. Supply service drops on industrial or commercial premises 54.8-B4a
2. Supply cables, grounded     57.4-G
3. Communication cables beside buildings, etc.    84.4-E
4. Communication conductors under bridges, etc.  84.4-F
5. Communication service drops.   84.8-C4

(v) May be reduced under special conditions.

1. Supply conductors of 750-7500 volts 54.4-H1
2. Supply transformer lead and bus wires where guarded 58.1-B

(w) May be reduced at angles in lines and transportation points

1. Supply conductors 54.4-D1
2. Communication Conductors 84.4-D5

(x) May be reduced for suitably protected lateral or vertical runs.

1. Supply bond wires     53.4
2. Supply ground wires     54.6-B
3. Supply lateral conductors     54.6-C
4. Supply vertical pins     54.6-D
5. Supply risers     54.6-E
6. Communication Ground Wires     84.6-B
7. Communication lateral conductors     84.6-C
8. Communication vertical runs     84.6-D
9. Communication risers 84.6-E

(y) Increased clearances for certain conductors

1. Unattached conductors on colinear lines and crossing lines 32.3
2. Unattached supply conductors     54.4-D3
3. Supply Service drops on clearance crossarms     54.8-C2
4. Supply Service drops on pole top extensions     54.8-C3
5. Unattached Supply service drops     54.8-D
6. Communication lines, collinear, conflicting or crossing     84.4-D3
7. Communication conductors passing supply poles and unattached thereto    84.4-D4
8. Communication service drops on clearance crossarms    84.8-D2
9. Communication service drops on pole top extensions     84.8-D3
10. Unattached Communication service drops   84.8-E

(z) Special provisions for police and fire alarm conductors require increased clearances 92.2

(aa) May be reduced under special provisions.

1. Supply conductors of 0-750 volts in rack configuration     54.4-D5
2. Supply service drops from racks     54.8-F
3. Supply cables and messengers attached to poles     57.4-F
4. Communication conductors on communication poles     84.4-D
5. Communication conductors on crossarms     84.4-D1
6. Communication conductors attached to poles     84.4-D2
7. Communication service drops attached to poles     84.8-B
8. Communication cables and messengers     87.4-D
9. Supply or communication cables and messengers on jointly used poles  92.1-B
10. Communication service drops on pole top extensions 92.1-C

11. Multiconductor cables with bare neutral 54.10-B1

12. Communication Conductors Across and Along Public Thoroughfares 84.4-A6

(bb)   May be reduced for Class T conductors of not more than 750 volts and of the same potential and polarity   74.4-D

(cc)   Not applicable to trolley span wires   77.4-E

(dd)   Special clearances for pole-top and dead-end construction

1. Conductors dead-ended in vertical configuration on poles     54.4-C4
2. Conductors dead-ended in horizontal configuration     54.4-D7
3. Conductors in pole-top construction   54.4-D8

(ee)   Clearance requirements for certain voltage classifications   54.4-D2

(ff)   Not applicable to communication conductors   84.4-D

(gg)   Clearance from crossarms may be reduced for certain conductors

1. Suitably insulated leads to protected runs     54.4-E
2. Leads of 0-5000 volts to equipment     54.4-E
3. Leads of 0-5000 volts to cutouts or switches   58.5-C

(hh) Reduced clearance permitted from temporary fixtures and lighting circuits 0-300 volts 78.3-A(1)

(ii) Special Clearances Required Above Public and Private Swimming Pools:

1.    Supply line conductors 54.4–A4
2.    Supply service drops 54.8–B5
3.    Communication line conductors 84.4–A5
4.    Communication service drops 84.8–C5
5.    Supply guys, span wires 56.4–A3
6.    Communication guys     86.4–A3

(jj) May be decreased in partial underground distribution 54.4-D2

(kk) Shall be increased by 0.025 ft. per kV in excess of 300 kV.

(ll) Shall be increased by 0.04 ft. per kV in excess of 300 kV.

(mm) proposed clearances to be submitted tot the CPUC prior to construction for circuits in excess of 550 kV.

(nn) Voltage shown in the table shall mean line – to – ground voltage for direct current (DC) systems.

(oo) May be reduced for grounded or multi-conductor cables.

1. Grounded cables 57.4-H

2. Multi-Conductor cables 54.10-B2

(pp) May be reduced to 4 feet for voltages below 7,500 volts 54.4-D3

(qq) May be reduced to 6 feet for voltages below 75 kV

(rr) May be reduced for supply service drops 54.8-D1

(ss) May be reduced to communication service drops 84.4-E1

(tt) Where a federal agency or surrogate thereof has issued a crossing permit, clearances of that permit shall govern.

(uu) Or Where sailboating is prohibited and where other boating activities are allowed

(vv) Clearance above contiguous ground shall be 5 feet greater than in cases 11 or 12 for the type of water area served for boat launch facilities and for area contiguous thereto, that are posted, designated or specifically prepared for rigging of sailboats or other watercraft.

(ww) For controlled impoundments, the surface areas and corresponding clearances shall be based upon the high water level. for other waters, the surface area shall be that enclosed by its annual flood level. the clearance over rivers, streams and canals shall be based upon the largest surface areas of any one–mile long segment which includes the crossing. the clearance over a canal, river or stream normally used to provide access for sailboats to a larger body of water shall be the same as that required for the larger body of water

(xx) Water areas are lakes, ponds, reservoirs, tidal waters, rivers, streams and canals without surface obstructions

(yy) May be reduced over non–walkable structures - Rule 54.8 (Table 10 )

(zz) May be reduced to 2 feet for conductors insulated in accordance with - Rule 20.9–G

(aaa) Special requirements for communication and supply circuits energized at 0 - 750 volts - Rule 35

(bbb) May be reduced for conductor of less than 60,000 volts when protected from abrasion and grounding by contact with tree - Rule 35

(ccc) For 22.5 kV to 105 kV, minimum clearance shall be 18 inches.

(ddd) Clearances in this case shall be maintained for normal annual weather variations, rather than at 60 degrees, no wind.

(eee) May be reduced to 18 feet if the voltage does not exceed 1000 volts and the clearance is not reduced to more than 5% below the reduced value of 18 feet because of temperature and loading as specified in Rules 37 and 43 .

Strikeout and Underline Version

Rule 37, Table 1

Table 1

Basic Minimum Allowable Vertical Clearance of Wire Above Railroads, Thoroughfares , Ground or Water Surface; Also clearances from Poles, Buildings, Structures or Other Objects(nn)

(Letter References Denote Modifications of Minimum Clearances as Referred to in Note Following this Table)

Case No	Nature of Clearance	Wire or Conductor Concerned
Case No	Nature of Clearance	A Span wires other than trolley span wires), overhead guys and messengers	B Communication conductors (including open wire, cables and service drops), supply service drops of 0-750 volts	C Trolley Contact, feeder and span wires 0-5000 volts	D Supply conductors of 0-750 volts and supply cables treated as in Rule 57.8	E Supply Conductors and supply cables, 750-22,500 volts	F Supply Conductors and supply cables 22.5 – 300 kV	G (mm)Supply Conductors and supply cables more 300 - 550 kV
1	Crossing above tracks of railroads which transport or propose to transport freight cars (max height 15 ft 1in) where not operated by overhead contact wires (a) (b) (c) (d)	25 ft	25 ft	22 ft	25 ft	28 ft	34 ft	34 ft
2	Crossing or paralleling above tracks of railroads operated by overhead trolleys (b) (c) (d)	26 ft (e)	26 ft (e) (f) (g)	22.5 Feet (h) (i) (eee)	27 ft (e) (g)	30 ft (g)	34 ft (g)	34 ft (g) (kk)
3	Crossing or along thoroughfares in Urban districts or crossings thoroughfares in rural districts (c) (d)	18 ft (j) (k) (ii)	18 ft (j) (l) (m) (ii) (aa)	19 ft (hh) (eee)	20 ft (ii)	25 ft (o) (ii)	30 ft (o) (ii)	30 ft (o) (ii) (kk)
4	Above ground along thoroughfares in rural districts or across other areas capable of being transversed by vehicles or agricultural equipment.	15 ft (k)	15 ft (m) (n) (p)	19 ft(eee)	19ft	25 ft(o)	30 ft (o) (p)	30 ft. (o) (kk)
5	Vertical ground in areas accessible to pedestrians only.	8 ft	10 ft (m) (q)	19 ft(eee)	12 ft	17 ft	25 ft (o)	25 ft. (o) (kk)
6	Vertical clearance above buildings and bridges (or other structures which do not ordinarily support conductors and on which men can walk) whether attached or unattached.	8 ft (r)	8 ft (r)	8 ft	8 ft	12 ft	12 ft	20 ft (ll)
6a	Vertical clearance above non-walkable surfaces on buildings, bridges or other structures which do not ordinarily support conductors except generating plants or substations wheather attached or unattached	2 ft	8 ft (yy)	8 ft	8 ft (zz)	8 ft	8 ft	20 ft
7	Horizontal clearance of conductor from buildings (except generating and substations), bridges or other structures (upon which men may work) where such conductor is not attached thereto. (a) (t)	--------------	3 ft (u)	3 ft	3 ft (u) (v)	6 ft (v)	6 ft (v)	15 ft (v)
8	Distance of conductor from center line of pole, wheter attached or unattached (w) (x) (y)	--------------	15 in (a) (aa)	15 in (aa) (bb) (cc)	15 in (aa) (o) (dd)	15 or 18 in (o) (dd) (ee) (jj)	18 in (dd) (ee) (jj)	Not Applicable
9	Distance of conductor from surface of pole, crossarm or other overhead line structure upon which it is supported, providing it complies with Case 8 above (x) (ee)	--------------	3 in (aa) (ff)	3 in (aa) (cc) (gg)	3 in (aa) (dd) (gg)	3 in (dd) (gg)	¼ pin spacing shown in Table 2 Case 15 (dd)	½ pin spacing shown in Table 2 Case 15 (dd)
10	Radial centerline clearance of conductor or cable (unattached) from non-climbable street lighting or traffic signal poles or standards, including mastarms, brackets and lighting fixtures , and from antennas that are not part of the overhead line system.	-------------	1 ft (oo) (u) (rr) (ss)	15 in. (bb) (cc	3 ft (oo)	6 ft (pp)	10 ft (qq)	10 ft (ll)
11	Water areas not suitable for sailboating (tt) (uu) (ww) (xx)	15 ft	15 ft		15 ft	17 ft	25 ft	25 ft (kk)
12	Water areas suitable for sailboating, surface area of: (tt) (vv) (ww) (xx) (a) Less Than 20 acrea (b) 20 to 200 acres (c) Over 200 to 2,000 acres (d) Over 2,000 acres	18 ft 26 ft 32 ft 38 ft	18 ft 26 ft 32 ft 38 ft	--- --- --- ---	18 ft 26 ft 32 ft 38 ft	20 ft 28 ft 34 ft 40 ft	27 ft 35 ft 41 ft 47 ft	27 ft (kk) 35 ft (kk) 41 ft (kk) 47 ft (kk)
13	Radial clearance of bare line conductors from tree branches or foliage. (aaa) (ddd)	-	-	18 in. (bbb)	-	18 in. (bbb)	¼ pin spacing show in Table 2, case 15 (bbb) (ccc)	½ pin spacing show in Table 2, case 15
14	Radial clearance of bare line conductors from vegetation in Extreme and Very High Fire Threat Zones in Southern California (aaa) (ddd) (hhh) (jjj)	-	-	18 inches (bbb)	-	48 inches (bbb) (iii)	48 inches (fff)	120 inches (ggg)

References to Rules Modifying Minimum Clearances in Table1

(a) Shall not be reduced more than 5% because of temperature or loading 37