Ian Malcolm wrote:

Pete C. wrote:
I think your going a bit overboard there, those precautions are a bit
more suitable for primary work or at lease 480V switch gear. Remember
that we are talking about 120V here, it doesn't take that much to
insulate against 120V, heck where you are you use 240V as your normal
household voltage. The threat in what's being proposed comes from the
high currents available, not from the voltage.

Bolt-on type circuit breakers are routinely connected live and not much
of a problem. The key thing is that there is generally a main breaker
upstream to shut things down in the event of a short. Working live
before the main breaker if there is a short things will stay lit up
until something melts open, doing a lot more damage.

Pete C.

Iggy is considering working on the feed to his panel. We presume there
is a supply company fuse somewhere upstream but with Iggy, who can tell?

The fuse will be on the primary side of the distribution transformer and
is unlikely to blow if someone shorts one phase in their panel.


With the exceptions of the gumboots, making sure you are clear of
sharp/spikey objects and keeping one hand in your pocket, everything
else is equally applicable even when working on 48 Volt BATTERY
supplies.

The construction details of all the code approved distribution panels in
the US take care of pretty much all the clearance issues.

With that in mind, does the fact that he's not likely to get
himself accross more than 120 V (though there is 240 V in there phase to
phase) make a lot of difference compared to 240 V panels over here.

Not a lot, only a small difference in the insulation necessary and any
decent electrical tape will be good for either.

As
I said, vaporised copper & steel is not your friend. If one of the
screws shears and the driver slips, what happens next?

Can't happen in the US panelboards (from the last few decades at least),
the top of the Allen setscrew is generally close to flush with the top
of the connector block. It's also a decent size Allen setscrew, like
5/16" or possibly 3/8" so it's unlikely to strip internally either.


Nearly everyone was concentrating on insulating the tool, not on
protecting Iggy. IMHO he needs to do *BOTH* so that if something goes
wrong, he's got a chance to come back and tell us how he *nearly* had a
bad accident, rather than the alternative.

We must presume that he has enough sense to not try this while standing
barefoot in a puddle, after all he hasn't killed himself with his RPC or
welder yet.

Pete C.



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Ian Malcolm. London, ENGLAND. (NEWSGROUP REPLY PREFERRED)
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