Commonly Asked Qustions
Q: What is the IP Ratings for an HSK-K (Nylon) fitting WITHOUT an O-Ring?
A: IP54 should be achieved without an O-Ring. It all depends on the surface. If the surface (contact point of Hex shoulder) is smooth an IP67 rating can be achieved. It is the customer's responsibility to test for higher ratings.
Q: Do ratings different between knockout and threaded installations?
A: No, they are the same!
Q: Why do HSK-M (Nickel Plated Brass) fittings come with O-Rings?
A: Because the material is harder and won't seal as well as a non-metallic (Nylon) fitting. All metal fittings must have an O-Ring.
Q: Do NPT fittings need O-Rings?
A: NPT fittings in threaded installations don't really require an O-Ring. Hex shoulder is not supposed to touch a surface. An NPT fitting used in a knockout installation should have an O-Ring if a higher than IP54 rating must be achieved.
Q: Is an O-Ring recommended in all 'wet' applications?
A: Yes, it is!
Q: What about wet spray but not submersed?
A: Hummel Cable Strain relief offer an IP69K rating as well. This is a protection in hose down / splash down environments (car wash, transportation, food processing, bottling plants, dairy, etc.). To meet this rating you must have an O-Ring installed.
Q: Is an O-Ring a better solution than a washer?
A: An O-Ring in a Sealcon Strain relief is in-bedded in an O-Ring groove and remains that way. A (Neoprene) washer as seen with competitive brands may 'explode' under pressure resulting in leakage / lose components.
Q: What else may affect a liquid tight installation?
A: Fit of cable in Strain Relief (snug fit is best), torque of SRF body in installation as well as dome top onto cable (seal), cleanliness of knockout (no burr), strong temperature fluctuations, vibration, pressure, etc.
How To's and Guides
Q: How to Drill out a Solid Insert?
A: To Start out we suggest drilling the solid insert wile frozen.
Step One, Drill holes by useing a standard high-speed steel drill bit of the proper size at approx. 2500 RPM.
Step Two, Drill holes with insert installed in Strain Relief Fitting as fixture.
Step Three, Keep a minimum distance of 1 mm (.04 in) between holes.
Note: The outside holes can be located right against the lip of the strain relief body, as such sufficient insert material remains between the hole and the body wall due to the design of the cord grip.
Important Design Parameters:
Cable diameter should NOT be less than 80% of hole diameter and the difference between hole and cable diameter should never exceed 1 mm (.04 in). The Multi Cable fittings will meet NEMA 4X = IP65 if the design parameters are complied with.
Note: To verify a submersible NEMA 6 = IP68 application, the final assembly of cables and fittings must be tested by the customer or submitted at the customer's expense to an independent test lab
Step One, Drill holes by useing a standard high-speed steel drill bit of the proper size at approx. 2500 RPM.
Step Two, Drill holes with insert installed in Strain Relief Fitting as fixture.
Step Three, Keep a minimum distance of 1 mm (.04 in) between holes.
Note: The outside holes can be located right against the lip of the strain relief body, as such sufficient insert material remains between the hole and the body wall due to the design of the cord grip.
Important Design Parameters:
Cable diameter should NOT be less than 80% of hole diameter and the difference between hole and cable diameter should never exceed 1 mm (.04 in). The Multi Cable fittings will meet NEMA 4X = IP65 if the design parameters are complied with.
Note: To verify a submersible NEMA 6 = IP68 application, the final assembly of cables and fittings must be tested by the customer or submitted at the customer's expense to an independent test lab
Q: How to feed a cable assembly with plug through a Strain Relief Fitting?
A: Once you know the largest dimension of the plug. Choose a strain relief fitting with appropriate dome opening as seen on Technical Data Chart. Next drill the solid insert to exact cable diameter and slice insert on one side only. Then assemble by feeding the connecter first through dome nut and strain relief body, snap the insert over cable and insert into body, tighten dome nut and Done!
Note: This applies to PG, NPT or Metric solutions.
Note: This applies to PG, NPT or Metric solutions.