Electrical
Advice From an Experienced
Professional
Dear
Mr. Electrician: I am installing a
sub-panel next to the main electric
service panel in my basement. What is
the best way to remove the pre-punched
concentric knockouts to the correct
size that I need without loosening the
remaining outer rings? Click
for detailed answer
Photos below are a demonstration of concentric knockout
removal.
Photo below
depicts the start of concentric knockout removal
with a view from the outside.
Start the removal by banging it in the direction
it was pre-punched from the factory.
Another photo below
depicting the start of concentric knockout removal
with a view from the inside
Photo below
depicts concentric knockout ring being rocked
forth and back using Channellock Pliers
Photo below shows
a concentric knockout ring being cut with BX Cutters
Another photo
below showing a concentric knockout ring being
cut with BX Cutters
The photo below
shows a concentric knockout ring that has been
cut.
This makes it easier to remove without
disturbing the remaining ring.
Below are the two
holes in the bottom of a sub-panel with the
knockouts removed.
The remaining burrs can easily be filed off if
necessary.
Below is a photo
of my BX Cutters.
If you punch out too big of a hole, you can use Reducing Washers.
If you punch out the wrong hole, you can fill it
with
a Knockout Seal.
.
.
