Cable Glands - Serrated Washers

[NickParker]

When the gland plate is less than 3mm, my company's procedure is to punch a hole (against threaded) for inserting the cable glands.

When it is a punched hole, we are instructed to use serrated washer.

Do this serrated washer provide enough sealing?

What are the pros and cons of using HDPE vs Nylon washers?

 

[7anoter4]

In my opinion it works. However contact the manufacturer. For instance:

https://www.hubbell.com/hawke/en/Products/Electrical-Electronic/Cable-Glands/Accessories/c/2146645

 

[prc]

As per my understanding serrated washers are giving the same function as lock nut. When you cannot use locknut (as shown in sketch by 7anoter4) serrated washers is one solution. HDPE/Nylon washers are for preventing moisture entry.

 

[rcw retired EE]

If the cable sheath is metallic, the serrated washers may be intended as a grounding/earthing connection between the cable sheath and the enclosure with the serrations digging into the metal. An HDPE/nylon washer still might work for sealing the exterior if the serrated washer or nut on the inside could still grip the enclosure to act as a locknut and make the connection. Manufacturer's instructions should be consulted.

 

[waross]

Adding a washer of any type to a gland connector could be called a code violation by the AHJ under our codes.
The contact between the gland connector body and the gland plate is a bonding path and as such, anything introduced into the bonding path must be approved for the purpose.
Even though a serrated washer may actually improve the bonding path by penetrating a surface covering such as paint, it must be approved for the purpose.
The ability of the serrations to pass high fault currents may be an issue and hence the need for certification and approval for use.
Note: I have been away from the commercial sector for quite a few years and if there are now approved serrated washers on the market I welcome the information.

If a gland entry must be sealed we have a couple of options.
One solution is to use a Meyers Hub.
The serrations provide metal to metal contact for bonding continuity and ensure that the paint layer is penetrated.
The compressible insert provides sealing. These hubs are common on industrial projects.

A seal ring is another option.
This is an approved plastic seal ring with a metal outer ring which provides bonding continuity.
Penetration of the paint layer is accomplished by the locknut on the other side of the gland plate.
These are common on commercial projects were biding is very competitive.

Gland connectors are available with a Meyers Hub type seal incorporated into the connector.

Bill
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Jimmy Carter