The problem here is that the previous solar company used fairly long
crimp lugs with heat shrink, which adds to the bending stress.
Also, its impossible to work in a Flex box with 2 inverters, 2 FM80s,
and the new triple shunt flex meter, and not be moving those #4 wires
around to say, land the 4/0 battery cables.
I personally think that UL dropped the ball and should not have let that
flimsy mount pass, or it should be listed for flex cable only. I did
plenty of prebending, but there just is no such thing as unstressed,
when landing a #4 or larger THHN.
Any other lug, in most other UL listed breaker boxes, is securely
mounted. When was the last time a lug snapped off in a Square D load
center? The breaker snaps out before it breaks. Panel mounted breakers
have to be sturdier than their snap in cousins, not less.
This is more than just an install PITA, it is a dangerous situation, as
the wire that snaps off could be hot from the battery, or from the
array. I also think its possible that the breaker could break later
after a few heat/ cool cycles, even if it didn't break initially .
Loose, energized wires inside a load center seems like a very bad idea.
As Kent pointed out, as soon as the tab bends up, it's game over. I was
considering a zip tie to secure the cable to the breaker, but the bottom
line is we shouldn't have to modify (and probably void the listing of)
UL listed breakers in the field. If I was doing something weird like
landing a 1/0 cable, I could see it was my problem. But you can't put
less than a #4 on an 80 amp breaker last time I checked, so the breaker
should be able to hold a #4 with some normal bending and jostling that
installations cause.
Ray
On 12/17/2011 8:39 AM, jay peltz wrote:
Hi Ray,
The only way I work on them with larger wire is with the breaker mounted in the
mounting plate and the mounting plate screwed in, then I bring the wire pre
bent/unstressed to the post.
Jay
Peltz Power
Sent from my iPad
On Dec 16, 2011, at 9:14 PM, Ray Walters<[email protected]> wrote:
Hi Folks;
Anybody else having trouble with the small Outback DC breakers snapping posts
off? I just took over a GTB job from another reputable GT solar company, after
they twisted off a post on an 80 amp breaker with #4 wire. I know those are
delicate breakers with low torque limits when tightening, so I took over. I
dropped the breaker mounting plate, so that I could work on the breakers, and
then I saw how weak the posts looked, just bending the #4 wires gently still
cause another breaker post to stress, and then break. I worked as gently as I
could, but I could not even get the plate back in position without damage.
In my opinion, those breakers are suspect with #6 wire, and they just can't
handle #4 or larger, unless maybe it was a flex type.
The old medium body Heinemans (125 amp) used to come in an 80 amp variety,
which was much sturdier. Is there an adapter that would let me use that type
of breaker on the Flexware box?
Ray Walters
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