Collection System - Grizzly G0785 Owner's Manual

Collection System

Material Selection
You have many choices regarding dust collection
ducting, but flexible hose is the most common for
this size of machine. However, be aware that there
is a fire or explosion hazard if plastic duct material
is used for dust collection without being grounded
against static electrical charge build-up.
Flexible rubber hose, polyethylene, plastic flex-
hose and other flexible ribbed hose is gener-
ally used for short runs. There are many different
types of flex hose on the market today. These are
manufactured from materials such as polyethyl-
ene, PVC, cloth hose dipped in rubber and even
metal, including steel and aluminum.
If using flex-hose, you should choose one of the
many types that are designed specifically for
the movement of solid particles, i.e. dust, grains
and plastics. However, the cost of specifically
designed flexible duct can vary greatly. Grizzly
offers polyethylene and steel flex hose.
Plastic duct generates static
electrical buildup that can
cause fire or shock. Properly
ground it to reduce this risk.
Duct Grounding
Plastic flex-hose is an insulator, and dust particles
moving against the walls of the hose creates a
static electrical build up. This charge will build
until it discharges to a ground. If a grounding
medium is not available to prevent static electrical
build up, the electrical charge will arc to the near-
est grounded source. This electrical discharge
may cause an explosion and subsequent fire
inside the system.
To protect against static electrical build up inside
a non-conducting duct, a bare copper wire should
be placed inside the duct along its length and
grounded to the dust collector. You must also
confirm that the dust collector is continuously
grounded through the electrical circuit to the elec-
tric service panel.
-16-
Be sure that you extend the bare copper wire
down all branches of the system. Do not forget
to connect the wires to each other with wire nuts
when two branches meet at a "Y" or "T" connec-
tion.
Ensure that the entire system is grounded. If
using plastic blast gates to direct air flow, the
grounding wire must be jumped (see Figure 12)
around the blast gate without interruption to the
grounding system.
Copper
Ground Wire
Figure 12. Ground jumper wire when using
plastic blast gates or elbows and metal duct.
We also recommend wrapping the outside of all
plastic ducts with bare copper wire to ground the
outside of the system against static electrical build
up. Wire connections at Y's and T's should be
made with wire nuts.
Attach the bare ground wire to each stationary
woodworking machine and attach the dust collec-
tor frame with a ground screw as shown in Figure
13. Ensure that each machine is continuously
grounded to the grounding terminal in your elec-
tric service panel.
Flex
Hose
External Ground Wire
Internal Ground Wire
Figure 13. Flex-hose grounded to machine.
Model G0785 (Mfd. Since 3/15)
Plastic Blast Gate
Metal Duct
Ground Screw