Glanding an armoured cable is an important electrical installation task that ensures the mechanical protection, earthing integrity, and environmental sealing of the cable, especially in industrial, commercial, and outdoor areas. When a cable gland is installed correctly, it will ensure electrical safety, keep the ingress protection (IP) intact, provide strain relief, and enable the system to perform well and last for a long time. On the other hand, if glanding is done incorrectly, it may cause loose connections, faulty earthing, moisture getting into the system, and probably electrical hazards.
This detailed and comprehensive tutorial will show you how to gland an armoured cable properly. It covers tools, preparation, best practices, and common mistakes that you should avoid, explained by Armoured Cable Manufacturers. The methods being explained are suitable not only for SWA (Steel Wire Armoured) cables but also for other types of armoured cables.
An armoured cable as per the armoured cable suppliers features a metallic protective layer (usually steel wire or steel tape) between the insulated conductors and the armour. This armour helps the cable to resist mechanical damage and impacts, and it also serves as a good earth path. However, if you want to benefit fully from the features of the armour, you have to use a proper cable gland to terminate (attach) the cable.
A cable gland has a number of functions, such as:
Besides, selecting a suitable gland type and size is as important as installing it correctly.
Step 1: Select the Correct Cable Gland
You cannot underestimate the importance of the first step, which is to select the right cable gland for your armoured cable. Your choice of the gland should be influenced by:
The cable diameter
Failure to use a properly sized gland will mean either a badly sealed installation or an insecurely terminated armour, both of which are safety and regulatory compliance issues.
Step 2: Prepare the Cable End
It is a good idea to measure the length of the cable that you will cut off first so that it will be long enough to reach the termination point without being too long for internal connections and glanding. After measuring, mark on the cable where you will strip off the outer sheath.
By means of a sharp cable stripping tool, gently score the sheath without cutting into the armour. When the sheath is scored all the way around, it can be peeled off carefully to reveal the steel wire armour all the way around the cable.
Accuracy here is very important, as any damage to the armour wires or insulation could lead to a weaker installation.
Step 3: Strip the Armour Correctly
On removing the outer sheath, the steel wire armour of the cable is revealed. The armour should be trimmed to the length that the gland manufacturer specifies, which normally means that the wires go under the gland’s armour clamping cone, and only the correct amount of wires will be shown.
The wires need to be cut in such a way that the cuts are clean and even. Do not do anything that will cause the wires to be bent, overlapped or splayed, as this will lead to a bad compression and a poor earth connection.
In case there is an inner bedding between the armour and conductors, carefully remove it without hurting the insulation of the conductors.
Step 4: Disassemble the Cable Gland
A typical cable gland contains a number of parts, which are as follows:
The correct orientation of the parts regarding the installation should be ensured by referring to the manufacturer's instructions.
Step 5: Insert the Cable into the Gland Body
Put the prepared cable end through the gland body. Spread out the armour wires around the clamping cone or ring so they lay evenly and naturally without twisting or bunching.
Continue pushing the cable until the inner bedding and insulated conductors come completely through the gland body. The armour should be placed in the clamping area in such a way that it is touching the whole circumference for effective earthing.
Step 6: Secure the Armour Termination
Gently move the armour clamping ring over the armour wires and into position. Tighten the gland body or clamping mechanism as per the instructions using suitable spanners.
This step guarantees:
You should not overtighten, as a hammer may crush the wires or strip the threads of the gland. The objective is a neat, uniform compression.
Step 7: Tighten the Outer Sealing Nut
When the armour is clamped firmly, tighten the outer compression or sealing nut. This action squeezes the sealing ring against the outer sheath, thus giving strain relief and preserving the enclosure’s IP rating.
A correctly tightened sealing nut will be:
Again, when torque recommendations are available, use them to prevent under- or over-tightening.
Step 8: Fix the Gland into the Enclosure
Put the gland into the enclosure’s cable entry hole. Check if the threads are fitting well and the gland is sitting flush with the enclosure surface.
Take the locknut and, from inside the enclosure, secure the gland with it. If the earth tag for bonding is required, place the earth tag properly between the gland body and the enclosure before the locknut is tightened.
This step provides a suitable electrical bond between the cable armour and the system earth.
Step 9: Terminate the Conductors
You are now at the stage to terminate the individual conductors after having the cable gland fully installed.
Strip each conductor as per the required length and hook them up to the terminals according to the wiring diagram or system specification.
Make sure all the joints are tight, correctly marked, and properly placed to allow enough airflow and to make future maintenance work easier.
Getting the Armoured Cables glanding done properly is anything but a normal operation—it entails the assurance of the three main factors, namely, mechanical protection, electrical safety, and environmental integrity. Moreover, the installers can get secure, compliant, and long-lasting cable terminations if they take a methodical, step-by-step approach and observe the best practices.
It is immaterial if you are dealing with an industrial control panel, a commercial distribution board, or an outdoor electrical system; mastering the right technique of armoured cable glanding is a must for safe and dependable electrical installations.