Review Wiring Regulations - Mettler Toledo IND780 Guide D'installation

IND780 Terminal Division 2 and Zone 2/22 Installation Manual
If the IND780 terminal does not include the approval information label as shown in
Figure 1-1 or Figure 1-2, the IND780 terminal cannot be installed in the hazardous
area.

Review Wiring Regulations

There are many methods that may be used to install properly approved equipment
within hazardous areas. In some cases, the field circuit characteristics (electrical
approval data) must be compared to those of the device connected to make sure
the combination is safe. In other situations, only a confirmation of a certain IP
rating and/or maximum surface temperature may be required to connect the
devices.
METTLER TOLEDO claims no expertise with respect to all the electrical regulations
that may be in effect at any specific location. You must refer to a national and/or
local electrical standards handbook for the safest installation possible that meets
all required standards.
Some national standards (including the NEC in the United States) require protection
of incendive lines such as the AC power line or PLC interfaces using conduit or
flexible conduit. This will require removal of the existing power cord and
installation of approved hardware such as increased safety glands or conduit
hubs. When new hardware connections are added to the IND780 enclosure, the
connections must maintain the integrity of the sealing of the enclosure.
It is recommended that the AC power be supplied to the terminal using a 1/2" or
3/4" conduit hub by making a hole in the upper part of the enclosure near the
power supply using an appropriately sized chassis punch. Keeping the AC power
entry near the internal power supply will help minimize electrical interference. The
centerline of the hole should be approximately 2" from the top edge of the
enclosure and 1
enclosure. When using the conduit hub instead of the supplied cable gland, the
original enclosure opening for the power cord should be sealed with the 16 mm
hole plug included with the terminal's standard bag of parts (#64057809) to
maintain the sealing integrity of the harsh enclosure.
PLC and other incendive signal lines can be supplied to the terminal using a 1/2"
conduit hub installed directly in the opening for either large cable plug. If a larger
3/4" hub is preferred, it can be installed by enlarging one of the large cable plug
positions. Refer to Figure 2-1 for an example of the installation of a 3/4" conduit
hub for AC power and a 1/2" conduit hub for the incendive signal lines.
2-2
THE IND780 TERMINAL IS NOT INTRINSICALLY SAFE! DO NOT USE WITHIN
AREAS CLASSIFIED AS HAZARDOUS DIVISION 1 OR ZONE 0/1 BECAUSE OF
COMBUSTIBLE OR EXPLOSIVE ATMOSPHERES.
7
/ " from the outside edge of the power supply side of the
8
WARNING