Re: looking for balanced power conditioner.

On Sun, 30 Sep 2007 08:58:07 -0400, Scott Dorsey wrote:

Most gear over is only fused in one leg, so you will need to supply
appropriate measures to deal with this.

Now, I thought the EU required switches and fuses on both legs now?

Nope, all power connectors (with a few irrelevant exceptions) are
polarised, the switch and fuse goes in the live, the neutral is assumed to
be current carrying but within a few volts of ground (The neutral is
however insulated to the same standard as the live).

I am always listening to American manufacturers bitching about how they
are forced to add these things when they aren't necessary in the US.

We tend to take EMC a little more seriously, and power supply safety very
seriously, but apart from that I don't see much difference.
There is however no equivalent of Underwriters Labs here, and the CE
certification is effectively a self certification that the product meets
the relevant standards (But god help you if you say it does and it don't).

RCD(GFCI) protection of the connected loads is good, but must cut both
poles (not all do).

Probably not good, actually, since one of the big advantages of balanced
power is being able to deal with clapped-out guitar amps that have major
chassis leakage issues.

If you have 30mA leakage (EU RCDs trip at between 15mA and 30mA for the
common ones), then that amp will fail to meet the safety requirements of
the electricity at work act (.UK, others have something similar), and
would fail any portable appliance test (Effectively required for work
equipment), so why are you using it? Get it on the bench and get it sorted.

Finally, remember that a fault from the 'neutral' to the case of any bit
go gear has the potential to put 120V on it (rather more dangerous then
the 60V you get for the same fault in the states).
True, but still less hazardous than 240V.

But with a single sided supply, that fault will blow the fuse within 0.4
seconds (probably well within), and the earth connection will keep the
touch voltage under control. If the gear has not been modified to fuse
both legs (which then has the potential to make it dangerous on a single
sided supply), you cannot make that statement about it when used on a
balanced supply.

It's a useful tool for a problem folks occasionally
encounter and it's worth keeping a little 200W balanced isolation box
around for when you encounter it. --scott

But you can get the same fix with a simple isolating transformer (with the
secondary treated as a separately derived supply), without the worries
about fusing.

I thought the OP was looking at a whole studio setup, which is what I have
major issues with.

Regards, Dan.
.

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