[R-390] RE:zzzzzzzzt, POOF!
Joe Foley
[email protected]
Mon, 6 Jan 2003 15:34:09 -0800 (PST)
--- polaraligned <[email protected]> wrote:
>
> >
> > How old are you? BX caused fires back in the 1960s
> and 1970s.
> > Well documented.
> >
> >
> > Ken Gordon W7EKB
>
>
>
> My question ken is that if fires caused by BX are
> well documented
> then why are so many commercial buildings required
> to use it?
++++++++
See my post regarding the newer style "BX".
> Why do whole citys require it?
+++++++
Easier/cheaper/faster remodeling. The average office
space is remodeled every TWO years!
> Was it an installation problem that caused the
> fires?
+++++++
YES, with the older style BX there was NO ground
except the outer covering which wasn't always tied to
the box or panel, which meant there was NO ground.
This was mostly on stuff installed in the '40's or
'50's that was still in use. Loose connections kept
the fuse/breaker from tripping because they couldn't
pass enough current to trip/blow, enough to heat
things up though. That from Dr. Jerry! But with no
ground path there was nothing to trip anyway unless
there was a solid short from hot to neutral. But this
also happened with wire run in conduit, too. The
problem with BX might have been the sharp edge at the
end of the metal jacket cutting through the
insulation, that's why you have to be sure to use the
little red anti-short bushings.
zzzzzzzzzzt! POOF!
Joe
> What was the mechanism by which the fires were
> caused?
> What is different now that it does not cause fires?
>
> Just trying to learn,
> Scott
>
>
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