Date: Mon, 04 Apr 2011 15:49:30 -0600
From: Doug Renwick <ve5ra@sasktel.net>
Subject: Re: [Amps] 4 wire 240VAC service? What to do now?
I looked at my Federal Pioneer sub panel and I do not see a neutral to
enclosure (ground) bonding screw or any where a screw has been removed.
Doug
### That's cuz they don't use a bonding screw..at least not in Canada. If you
look closely
at any main 100/200A panel.... you will see there is a place to install an
offset piece of
copper buss bar. They typ look sorta like 1/2 of a swastika. Goes from
one end of the
floating neutral buss to metal case. The bozo who installed the main 200A
panel for the previous
owner had left the buss bar strap..out of the circuit....and sitting at the
bottom of the new
200A main pane! The 4 x screws for the 200A breaker were all semi loose
too...so I cleaned
up the entire panel...and checked ALL the various connections..including all
breakers. I'm wondering if the
contractor who did the work obtained a permit..or not. In a lot of cases, the
electrical inspector never shows up
to check the work of contractors.... too busy, and too few inspector's.
## I later added a 100A sub panel....and of course the bonding strap between
neutral buss and metal
casing is NOT used on any sub-panel. The 4th wire [ green] is to handle
FAULT current only..hence
the electrical code states that the neutral to metal casing strap must be
removed on any sub-panel.
## That shorting strap is installed with 2 x heavy duty tapped holes and mating
screws.
## OK..now if your sub panel is a real small one like a 20-60A panel.... it
may well not have provisions
for the bonding strap....since it would never be used as a main entrance panel
. The smallest service
we can have in a home, for a main panel here in town is 60A. My sister has a
60A main panel..but her home
is pretty old. Mine is 1953 vintage..and had a 70A panel. It was upgraded to
200A just before I bought it in 1997.
## You can usually find the info on the manufacture's website. Sometimes the
bonding strap is in the middle section of the
floating neutral buss. The tapped holes may well be buried under a myriad of
existing wirings, but it will be there.
## I did notice that on the big 200A panels....that depending on which
province you are in, each province will have
different max quantities of the smaller breaker's allowed in the 200A panel.
In some cases, the outer cover is made with solid steel
where the typ 'knock outs' are located......so there is no way to install
additional breakers beyond the max limit.
## The panels to avoid are the 'stab-lock' variety. A dumb design ..and
dangerous at best. One side of each individual
breaker ends up making a lousy connection.
later.... Jim VE7RF
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