On 01/05/2018 19:25, Jimmy Wilkinson Knife wrote:
On Tue, 01 May 2018 15:41:19 +0100, wrote:

On Tue, 01 May 2018 12:40:23 +0100, "Jimmy Wilkinson Knife"
wrote:

On Sun, 29 Apr 2018 04:46:08 +0100, wrote:

On Sat, 28 Apr 2018 19:56:21 -0700 (PDT), trader_4
wrote:

On Saturday, April 28, 2018 at 10:09:06 PM UTC-4, Jack wrote:
On 4/28/2018 8:33 PM, trader_4 wrote:
He's not obsessed with code, he merely pointed out to you that you
don;t know WTF you're talking about,*again*, and Edison circuits
are normal, safe, and MEET CODE.* The neutral current will never be
greater than the breaker rating. For example, a 20A circuit will
have 20A breakers and use 12g wire.* There will never be more than
20A flowing in the neutral.

* Yes, Edison circuits MEET CODE but because of the potential
mayhem lurking with an unbalanced load and a loose neutral, you
won't find one in my house.* Too much risk, not enough reward.

Yes, that's a different question, whether they are worth it or not.
I don't necessarily disagree with you. Another* issue is that some
homeowner
who knows something about electricity, but like JWS doesn't understand
how they work, screws around with it in the future.* But the point
here
was that they do work, they don't somehow overload the neutral and
that
is recognized by them being described in the code and acceptable.

The main advantage is reduced voltage drop on a circuit that goes to
the far end of the house. You might even find them that you don't know
about because they were not required to be on a 2 pole or handle tied
breaker until fairly recently.
The requirement to have a common trip was applied to multiwire
circuits in 1987 but only if both sides landed on the same yoke. (a
split receptacle) There was no requirement before that. It was not
until 2008 that the NEC required all multi wire circuits to have a
common trip. When you understand that most jurisdictions take a while
to adapt the new code. you can have a pretty new house with a
multiwire circuit landing on 2 single pole breakers that are not even
required to be grouped, much less handle tied.
The typical multiwire circuit in a house will feed bedrooms or general
lighting loads on the far end of the house and be split out in a
ceiling box so they never land on a single yoke. .

You get less voltage drop if you use a decent voltage instead of a
namby pamby one.

The voltage drop on a multiwire circuit is based on 240v

If you happen to evenly spread the load.

and you only have 220. Who is namby pamby again?

Actually my mains voltage is 245.* The UK used to be 250 and is now 240
(ish).* 220 is for places like France.

Just as it was in 1960, the supply voltage to domestic properties in the
UK is still nominally 240 V AC at 50 Hz, although the declared voltage
in the UK is now 230V AC +10% to -6%. Historically the domestic voltage
was 240 V +/-6% (and 415V 3phase), whilst continental Europe was 220V
(380V 3 phase).

Environmental Technology Centre | Voltage Optimisation
https://www.nottingham.ac.uk/etc/gui...timisation.php
--
Bod