What it will be is:
90? up to another 90?
then approx 41' straight run ending in an LB
This will all be at the top of the outside wall up against the soffit
Then from the LB, which is being used to turn the corner, to a 90?
from the 90? down to another 90?
straight run of approx 26' ending in an enclosure
The bottom run (26') will be behind landscaping (read bushes, shrubs, etc) mostly out of the sun. Would it also need an expansion coupling?
1) Figure out the lowest expected temperature for the year. Call it L.
2) Figure out the highest temperature for the year. Call it H.
3) If the conduit is run on a roof get the additional value from Table 310.15(B)(3)(c) using the climate data for your location, call it
R.
4) If not on a roof assign zero to R.
5) Determine the maximum temperature difference H + R - L. Call it T.
6) Look in Table 352.44 under "Temperature Change (?F)" for the value greater than or equal to T.
7) Note the corresponding value under "Length Change..." beside the entry found in step 6. Call it E.
8) Divide the length of each straight run in feet by 100 feet, Call that F.
9) Multiply E and F, call the result M.
10) If M is less than ? (0.25) inches, no expansion fitting is required.
11) If M is greater than ? (0.25) inches, one or more expansion fittings are required.
12) Determine the maximum slip length in the expansion fitting for the size conduit you are using, call it S.
13) If S is greater than or equal to M, then you need one expansion fitting.
14) If S is less that M, Divide S by M. Call the answer N.
15) If there is no remainder (or fractional part) from the division, you need N expansion fittings.
16) If there is a remainder (or a fractional part) from the division you need N + 1 expansion fittings.
17) Determine the installation temperature, call it C.
18) Subtract C - L, call it X.
19) Divide X by T, call it Y.
20) Multiply Y by S, call it Z.
21) Z (using the fractional part) is the number of inches from shortest you need to set the expansion fitting(s) when you install the
fitting. Suggest you mark it on the inner tube of the fitting.
22) Save your calculations in case the inspector wants to see them.
SUMMARY:
L = lowest yearly temp
H = highest yearly temp
R = additional factor for roof heating
T = maximum temp difference
E = expansion in inches/100 feet
F = hundred foot equivalent
M = maximum expansion
S = slip length of an expansion fitting
N = number related to number of expansion fittings
C = current temp
X = current temp less lowest temp
Y = ratio of current temp to highest temp
Z = setting, in inches upon installation.
Input:
L, H, S, C
Lookup:
R, E
Calculations:
T = H + R - T
F = (run in feet) / 100
M = E * F
N = M / S
X = C - L
Y = X / T
Z = Y * S
