Patburmeister
New member
- Location
- Denver CO USA
I am running 6 4" EMT runs on rooftop crossing 1 building expansion joint. Total length is 360 feet. I cant find in code book how many I need.
Expansion fittings
- Thread starter Patburmeister
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LarryFine
Master Electrician Electric Contractor Richmond VA
- Location
- Henrico County, VA
- Occupation
- Electrical Contractor
1. Welcome to the forum.
2. Too much for me to look through:
Expansion joints (fittings)
250.98,
300.7(B), 352.44,
355.44, 366.44,
368.244, 424.44(C),
424.98(C),
424.99(C)(1), 426.20(E),
426.21(C), 426.22(D),
427.16
2. Too much for me to look through:
Expansion joints (fittings)
250.98,
300.7(B), 352.44,
355.44, 366.44,
368.244, 424.44(C),
424.98(C),
424.99(C)(1), 426.20(E),
426.21(C), 426.22(D),
427.16
GerryB
Senior Member
- Location
- woodbridge, ct. USA
I have seen some solar rooftop jobs, emt, not as long, but they used an expansion joint only at the building expansion joint.
oldsparky52
Senior Member
- Location
- Wilmington, NC USA
bad vision on reading the post
Last edited:
- Location
- New Jersey
- Occupation
- Journeyman Electrician
What Gerry said. 
rambojoe
Senior Member
- Location
- phoenix az
- Occupation
- Wireman
In AZ it would be one every 100'. And anything more than 20' also needs derating for heat but im sure the engineer took care of that...some where I have a handbook that has stats on expansion but you should be able to search for that.. I think its every 120' but we would do a bit more. and in the SW you can expect a ridiculous amount of condensate in the winter- with still fairly warm days and very cold nights, just something I always keep in mind.
that's a lot of weight- was it designed above roof joists?
that's a lot of weight- was it designed above roof joists?
- Location
- New Jersey
- Occupation
- Journeyman Electrician
Even for EMT?
rambojoe
Senior Member
- Location
- phoenix az
- Occupation
- Wireman
I need to find that field handbook, but again- that would be the boss saying what he wants. im still trying to visualize a rooftop expansion joint, wouldn't it just look like a double block wall coming through the roof? ive seen slab expansion joints in slabs but those required going from emt/rmc to flex, not expansion joints...
maybe one of you fellahs has a set of A sheets with a engineers detail on these fittings/transitions. I could guess on each 10' piece but the total length is more important than the 3/16" expansion and cooling. I do know that 35 sticks is significant, that's why the fittings slide so much... hell I don't know. thanks to a gazillion solar start ups around here, they sure have revised a lot rules for everyone...
alright you engineers- put down the adult beverage and chime in!
p.s., it sure is obvious when a long raceway on a roof is expanding- when you see the dirt ring around the roof jacks about 4" away...which is why some guys cut the roof material and put it under the stands- slides a bit better...
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