I've been using clamps like this for 3/8" Flex and 1/2" knockouts:
<(Amazon.com product link shortened)>. They work fine, you just tighten
the two bolts and the flex cable is gripped and strain-reliefed.
Home Depot had these that were a little cheaper and use only one bolt:
<(Amazon.com product link shortened)>.
I must be doing something wrong here. The latter clamps, with the single
bolt, do not grip the 3/8" flex cable even with the bolt tightened all
the way down. What is the purpose of the clamp on these since the clamp
is too big to grip the flex cable? I returned most of them to the store
and bought the kind I'd been using. But I must be doing something really
stupid for the single bolt type to not work.
Maybe not the right size?
I think you have to look at the listing tho. Some may be listed for
whips and others only when the cable is supported within a foot of the
box. In that case, the clamp is not really holding that much.
From 2 screw model:
Sigma Electric C-510 BX/MC/FLEX 3/8-Inch Combination Connector
From 1 screw connector:
Halex 90420 3/8-Inch Flex Squeeze Connector
Both should work fine if the flex is not distorted in the cutting
process and is inserted and tightened properly.
The second connector may have been switched with a 1/2 flex connector
which may fail to tighten.
I have used both geometries with success.
The "squeeze" type are only listed for installations where the cable
is supported within 12" of the box. It's only function is to make an
electrical connection, not a mechanical one.
We used to fight them all the time under computer room floors.
On 2/19/2015 5:11 PM, firstname.lastname@example.org wrote:
What does that mean? The clamp is essentially a strain relief to hold
the aluminum sheath of the flex, mechanically. With the single screw
clamp you tighten it all the way down but the diameter of the clamp is
too large to grab the sheath of the 3/8" cable. I suppose that it also
grounds it if the steel boxes are grounded through the outlet and switch
On Thu, 19 Feb 2015 23:31:12 -0500, email@example.com wrote:
Flexible Metal Conduit trade size is ID, OD is bigger so a 3/8 FMC
will be about .61"
MC cable is not the same thing. It actually ends up being .47" in 14-2
with ground. It is .49" in 12-2/wg
The NEC handbook says "FMC fittings are not considered to be a means
of cable support."
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