44 SEPTEMBER 2015 | FUEL OIL NEWS | www.fueloilnews.com
HVAC/ HYDRONICS
public and personal safety, and then
everyone is amazed the stuff works right
too," Bill said. "If you work on equip-
ment, you must check your ground."
In the middle 1960s, UL demanded
that OEMs provide for proper ground-
ing and those little green screws showed
u p . W h e n a p i e c e o f e q u i p m e n t i s
designed and tested, proper ground-
ing is on the job. When warranties go
back and the control you took off as
not working now works in the factory
it's your fault. Keep in mind that at the
factory those OEM test benches are to
the book and grounded. One thing I
notice a lot is that in conversations guys
admit that they "took off the new stuff,
put on ol' reliable and it worked great."
There are only two problems with that
statement: ol' reliable won't do as many
things as the new ones, and they are also
not as sensitive to grounding. There's
just less of or no solid-state in those ole-
time boxes.
Proper grounding is very easily veri-
fied, but do you know how? Well, here's
my most favorite way. First of all, take a
common light-bulb holder, one of my
all-time favorite pieces of test gear. Take
it and put it across a known circuit, it
should light. Then, put it between your
hot or power (L1) line and your neutral
(L2) line, it should light again. Now,
put it between hot and ground, Figure
2, again it should light and that proves
your ground. Finally, put it between
ground and neutral and it should not
light. If it does, you have a short circuit
somewhere between neutral and ground
and that must be fixed right away. Don't
count on the conduit to provide the
ground either. Unfortunately, some
people doing the wiring today drop the
ground going through plastic boxes,
Figure 2
