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5 INSTALLATION
Following these installation instructions will consistently
produce satisfactory MI cable installations. Further
information on proper installation techniques may be
obtained by contacting nVent Technical Support, see
Section 1.1.
5.1 General Installation Guidelines
•
When subject to potentially damaging abuse, protect
the cable with a metal guard such as angle iron or steel
channel.
•
Metal supports, cable sheath, and other metal
enclosures for the cables must be metallically joined
together and must be connected to all boxes, fittings,
and cabinets so as to provide effective electrical
continuity.
•
Ensure that you do not invalidate the listing of
enclosures or other equipment if it is necessary to cut
holes.
Moisture Absorption
The magnesium oxide insulation of MI cable is
hygroscopic and can absorb moisture when exposed to air,
causing the IR to fall. Low IR can be corrected as outlined
in Appendix A.
Expansion and Vibration
Where cables may expand or contract due to temperature
changes, or when connecting the cable to vibrating
equipment, it may be necessary to take precautions to
prevent mechanical damage to MI cable. Refer to Section
5.2, page 23 and Section 5.3, page 26 for further details.
Equipment Bonding
The sheath of Alloy 825 MI cable must be bonded to
ground, but must not be used as the equipment-to-ground
bonding conductor. For proper equipment-to-ground
bonding, use one conductor within the sheath or use a
separate equipment-to-ground bonding conductor.
Straightening and Dressing the Cable
The cable may be straightened by hand or by using a dead
blow hammer and a block of wood as shown in Figure 8.
Do not use a metal hammer as it may result in unsightly
dents that cannot be removed. Once the cable has been
installed, the use of stainless steel banding or cable
clamps to strap the cable to the tray will help dress the
cable, maintaining a neat appearance.
nVent.com | 15
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