Cable glands are one of the most overlooked components in roll forming electrical systems.
They are small.
They are inexpensive.
They are often installed quickly.
Yet they directly affect:
IP rating compliance
Cable strain relief
Ground continuity
EMC stability
Moisture ingress
Dust contamination
Long-term reliability
Improper cable entry sealing is responsible for:
Water inside cabinets
Steel dust contamination
VFD failure
Corroded terminals
Ground faults
Insulation breakdown
This guide explains how to engineer cable glands and entry sealing properly for industrial roll forming and coil processing environments.
Cable glands serve four primary functions:
Provide strain relief
Maintain IP rating
Seal against dust and moisture
Ensure grounding continuity (where required)
They are not simply “holes for cables.”
They are mechanical and electrical safety devices.
Used for:
Control cables
Low-voltage circuits
Indoor IP54 environments
Advantages:
Lightweight
Cost-effective
Corrosion resistant
Limitations:
Lower mechanical strength
Limited EMC shielding capability
Used for:
Power cables
Outdoor cabinets
Harsh environments
Advantages:
High mechanical strength
Better grounding capability
Suitable for IP65/IP66
Common in roll forming structural lines.
Special glands designed to:
Provide 360° shield termination
Ensure proper cable shield bonding
Critical for:
VFD motor cables
Encoder cables
High-frequency switching environments
Improper EMC gland selection causes:
Noise
Encoder errors
PLC instability
Cabinet IP rating depends heavily on:
Door seals
Gasket integrity
Cable gland sealing
A cabinet rated IP65 becomes IP20 if:
Glands are improperly tightened
Wrong gland type is used
Entry holes are oversized
Unused holes are left open
Entry sealing must match cabinet IP design.
Cable glands must provide mechanical retention.
Without strain relief:
Cable weight pulls on terminals
Vibration loosens connections
Insulation damage occurs
Terminals overheat
Roll forming machines vibrate.
Structural lines with heavy forming loads transmit vibration through cable systems.
Proper gland torque is essential.
Best practice:
Separate cable entries by function:
Left side: Power cables
Right side: Control cables
Bottom plate: Field motor cables
Never route high-current motor cables through same gland plate area as encoder cables.
Physical separation reduces EMC interference.
Motor Section:
VFD → Shielded Motor Cable → EMC Gland → Motor
Sensor Section:
PLC Input → Shielded Sensor Cable → Plastic Gland → Sensor
Safety Section:
24V → E-Stop Cable → Gland → Field Device
Each cable class should have its own defined gland zone.
For VFD motor cables:
Correct configuration:
VFD → Shielded Cable → 360° Shield Clamp / EMC Gland → Cabinet Ground
Incorrect shield termination causes:
High-frequency leakage
Bearing currents
Encoder noise
Drive faults
EMC glands are critical in VFD-heavy roll forming cabinets.
Common failure patterns:
Outdoor cabinet without proper gland sealing
Over-tightened glands damaging cable sheath
Under-tightened glands allowing moisture entry
No drip loop on vertical cable runs
Water inside cabinet leads to:
Corrosion
Short circuits
Control PSU failure
Arc flash risk
Proper sealing prevents catastrophic failures.
Gland plates must:
Be removable for maintenance
Be properly sealed to cabinet frame
Support correct gland spacing
Maintain structural integrity
Laser-cut gland plates are common.
Ensure unused holes are sealed with certified blanking plugs.
In humid climates:
Temperature changes cause condensation inside cabinet.
Cable entry areas must:
Prevent moisture tracking along cable sheath
Include drip loops
Avoid direct vertical water flow into gland
Sealing does not eliminate condensation risk — environmental control is required.
In heavy industrial environments:
Armored cables may be used.
Glands must match:
Armor type
Cable diameter
Mechanical load
Incorrect gland type reduces mechanical strength.
Large power cables expand and contract with temperature.
Poor gland installation can:
Damage insulation
Loosen termination
Create stress on busbar
Gland selection must account for cable diameter tolerance.
Using plastic glands for heavy motor cables
Ignoring EMC gland requirements
Not tightening to manufacturer torque
No separation between power and control entries
Oversized drilled holes
Leaving spare holes unsealed
No drip loops in outdoor installations
No bonding of metal gland to PE
Small mistakes here create large electrical problems.
When exporting roll forming machines:
Check:
Climate (humidity, sand, rain)
Outdoor vs indoor installation
IP requirement
UV exposure
Salt air exposure (coastal regions)
European IP54 gland strategy may fail in Middle East IP65 environment.
Entry sealing must match destination.
Before commissioning a machine, ask:
What IP rating is cabinet designed for?
Are glands matched to cable diameter?
Are EMC glands used for VFD motor cables?
Are unused holes sealed properly?
Is strain relief verified?
Are gland plates removable?
Is separation maintained between power and control entries?
Is installation environment considered?
Red flag:
“All cables go through one hole with silicone.”
This is not industrial practice.
They provide proper shield termination and reduce high-frequency interference.
Not recommended for high-current or harsh environments.
No. Condensation can still occur internally.
Yes. Power and control cables must be physically segregated.
Indirectly yes — vibration and strain can loosen terminals.
Ignoring EMC requirements for VFD motor cables.
Cable glands and entry sealing in roll forming control cabinets must ensure:
Proper IP integrity
Reliable strain relief
Correct EMC grounding
Mechanical durability
Environmental protection
Separation of power and control
They are not cosmetic accessories — they are part of the electrical safety and reliability system.
Poor entry design introduces contamination, noise, and premature failure.
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