29 Sep 2017
After major storms and flooding circumstances like we have had during this hurricane season, Allied Tube & Conduit® fields many questions regarding the continued use of or cleaning of steel conduit and EMT exposed to storm and flood waters.
Allied Tube & Conduit® is a member of the National Electrical Manufacturers Association (NEMA). NEMA has a brochure on Evaluating Water-Damaged Electrical Equipment. The Steel Conduit/EMT Section of NEMA provides the following information on page 7:
4.5.2 Conduit and Tubing
In the case of flooding, fire-fighting activities or other instances of unusual water exposure, conduit and tubing must be carefully inspected to determine if the mechanical and electrical integrity of the conduit/tubing system has been compromised. Flood waters, in particular, may be contaminated with oil, chemicals, sewage and other debris that could enter the conduit/tubing and prevent a clear path for the replacement of conductors or cables. As part of the inspection process, assure that the interior of the conduit/tubing is clear. In addition, contaminants may also affect the physical properties of metallic and nonmetallic materials and the corrosion protection for electrical equipment as required in NEC Section 300.6. Since every situation has unique circumstances the services of an experienced evaluator should be used. The manufacturer can also be consulted for additional assistance.”
Note that the section recommends, “since every situation has unique circumstances, the services of an experienced evaluator should be used.
If an experienced evaluator determines that the integrity of the conduit or EMT has not been compromised and replacement is not necessary, the conduit or EMT can be cleaned with a simple soap and water flush to remove salts from the flood water. Caution should be exercised when drying conduit or EMT with a heat source to avoid discoloration and/or damage.