Bulletin 1728F-804: Specifications and Drawings for 12.47/7.2 kV ...
Bulletin 1728F-804: Specifications and Drawings for 12.47/7.2 kV ...
Bulletin 1728F-804: Specifications and Drawings for 12.47/7.2 kV ...
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Calculation of Maximum Line Angles<br />
<strong>Bulletin</strong> <strong>1728F</strong>-<strong>804</strong><br />
Exhibit 1<br />
Page 1<br />
The following <strong>for</strong>mula <strong>and</strong> the data tabulated below were used to calculate the maximum<br />
line angles on pin <strong>and</strong> spool insulator assemblies:<br />
P − ( Fw×<br />
Sw×<br />
Ww)<br />
Sin(θ<br />
/ 2)<br />
=<br />
2 × Ft × T<br />
Where:<br />
θ = Maximum Line Angle (calculated): [Degrees]<br />
P = Designated Maximum Transverse Load (allowed on pin or insulator): [lbs]<br />
Fw = Wind Overload Factor <strong>for</strong> Transverse Loads<br />
Ft = Wire Tension Overload Factor <strong>for</strong> Transverse Loads<br />
Sw = Wind Span (equals ½ sum of adjacent spans): [ft]<br />
Ww = Wind Load on Conductor: [lbs/ft] (See Table Below)<br />
T = Design Tension of Conductor: [lbs] (See Table Below)<br />
From NESC Table 253-1 <strong>for</strong> Grade C Construction:<br />
⎡ P − ( Fw×<br />
Sw×<br />
Ww)<br />
⎤<br />
θ<br />
= 2 × Arcsin⎢<br />
⎣ 2 × Ft × T ⎥<br />
⎦<br />
Fw = 1.75 <strong>for</strong> non-crossing spans (Footnote 4 to Table 253-1)<br />
= 2.20 <strong>for</strong> crossing spans<br />
Ft = 1.30<br />
CONDUCTOR Maximum Design<br />
SIZE & TYPE Strength Tension Tension (T)(lbs)<br />
4 ACSR (7/1) 2360 60% 1416<br />
2 ACSR (6/1) 2850 60% 1710<br />
2 ACSR (7/1) 3640 60% 2184<br />
1/0 ACSR (6/1) 4380 60% 2628<br />
123.3 AAC (7) 4460 60% 2676<br />
2/0 ACSR (6/1) 5310 50% 2655<br />
3/0 ACSR (6/1) 6620 50% 3310<br />
4/0 ACSR (6/1) 8350 40% 3340<br />
246.9 AAC (7) 8560 40% 3424<br />
336.4 ACSR (18/1) 8680 40% 3472<br />
336.4 ACSR (26/7) 14100 35% 4935<br />
WIND LOAD (Ww) (lbs/ft) by NESC Loading District<br />
LIGHT MEDIUM HEAVY<br />
4 ACSR (7/1) 0.1928 0.2523 0.4190<br />
2 ACSR (6/1) 0.2370 0.2720 0.4387<br />
2 ACSR (7/1) 0.2438 0.2750 0.4417<br />
1/0 ACSR (6/1) 0.2985 0.2993 0.4660<br />
123.3 AAC (7) 0.2985 0.2993 0.4660<br />
2/0 ACSR (6/1) 0.3353 0.3157 0.4823<br />
3/0 ACSR (6/1) 0.3765 0.3340 0.5007<br />
4/0 ACSR (6/1) 0.4223 0.3543 0.5210<br />
246.9 AAC (7) 0.4223 0.3543 0.5210<br />
336.4 ACSR (18/1) 0.5130 0.3947 0.5613<br />
336.4 ACSR (26/7) 0.5408 0.4070 0.5737
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