Thoughts on failed adapter fitting, 2" HDPE to Liquidtite

rezonatefreq907

rezonatefreq907

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Location
USA
Occupation
Utility
Performed a one year warranty inspection on a 200kW PV array yesterday. Coated metallic flex (Liquid Tite) use extensively for DC and AC. HDPE used under ground. Notice the use of some type of adapter fitting from the liquid tite to HDPE. They have and overall heat shrink covering. The adapters are right where the flex transitioon under ground. They had about 1 ft of heat shrink over the entire adapter. Happened to slightly pull on one of the adapters and it felt loose. The adapter separated easily from the HDPE exposing the conductors. Cut off the heat shrink and noticed the 2" adapters components: coated metal flex raceway, flex male connector, GRC threaded coupling, short nipple of GRC, SUR-LOC adpter, HDPE pipe, heat shrink over wrap. This Sur-loc supposedly rated for 700lb pull out. Maybe the expansion and contraction of Alaska summer and winter along with water gathering in the slight depression from trench excavation caused failure. The workmanship seemed good. Only noticed two failures on the longest runs of HDPE, and they both had water pooled around adapter and are on the bottom of sites slight grade down hill. This adapter assembly is used multiple times on the site.

The HDPE adapters I am familiar with have barbs in them not really reusable and are irreversible.

Any thoughts on the install, parts and or what is the recommended feasible repair. Have concerned about the longterm life of this method.

https://imgur.com/a/bDq3rbi
 
ptonsparky said:
There are adapters for HDPE to PVC. Use those then adapt as needed with pvc fittings to your nonmetallic seal tight. IDK if the metallic version is approved for direct burial. PP idea even if it is.
Click to expand...
The flex is metallic. The barbed mechanical couplings I have used in the past have 1400 lbs pull out vs 700. Seems like a poor design or mis application to rely on a hose clamp to hold the hdpe. Maybe becuse it was at grade a not buried?

SPEC SHEETS | CoBALT Couplers

www.cobaltcouplers.com www.cobaltcouplers.com
 
rezonatefreq907 said:
The flex is metallic. The barbed mechanical couplings I have used in the past have 1400 lbs pull out vs 700. Seems like a poor design or pmis application to rely on a hose clamp to hold the hdpe. Maybe becuse it was at grade a not buried?

SPEC SHEETS | CoBALT Couplers

www.cobaltcouplers.com www.cobaltcouplers.com
Click to expand...
Is the flex..."For direct burial where listed and marked for the purpose." 350.10(3)

Buried LFMC is sort of like the rubber washers that are put on EMT RT connectors. Pretty Poor design, or words to that affect.

Those couplers are dang hard to get on. I wouldn't think you could get them off if tied to hitch on my Ram. Not installed properly?
 
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