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One of the joys of living in the United Shires is our glorious
domestic
electrical systems. If I were to nit-pick, however, I'd have to say
that
wiring a new electrical outlet can be a bit of a pain in the arse.
The
issue is that up to three cables (two ring main plus a spur) have to
be
terminated at the fascia. Each cable carries three conductors
and
at least six inches of slack wire is required so that the fascia can
be
pulled away from the wall for installation/inspection. That's
3x3x6"=54"=4.5ft of wire which has to be folded up inside the
backbox. This very often leads to mechanically strained cables
which
have a tendency to pull out. It looks rubbish too.
The proposed solution is to terminate the conductors within the
backbox. The box would contain live, neutral and earth bus bars
to
which incoming cables would be directly connected. This would
eliminate the need for any excess cable. The electrical connection
to the fascia could then be via a single three-core fly-lead or,
preferably, through an integrated 3-pin plug/socket connector.
Further advantages of this system are that the professional
electrician can finish his/her job at first fix (pre-plastering)
because
the fascias can be easily installed or replaced by the unskilled
home
owner without isolating the circuit. Furthemore the backbox is
automatically earthed, which is commonly overlooked. There
would
be a small increase in materials cost but this should be easily
offset
if the electrician doesn't have to return to complete the second
fix.
[link]
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This is an excellent idea. I get sick of trying to keep
excess cable tidy in the limited space behind a
socket. It usually ends up getting jammed in, with
only the facia screws providing the necessary
compressive force to pack the whole lot down. |
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There is something unclear here. Many backboxes are
steel, and already have screw-holes for the ground/earth
wire. There could be some risk installing the specified bus
bars inside such boxes. Other backboxes are made of
plastic, so the phrase "automatically earthed" needs more
details of explanation. |
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In the UK, steel backboxes are the norm (I'm not sure
if they're mandatory - I think not). |
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I don't see why there's a risk having a bus-bar and
connections built into a steel backbox. |
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[MaxwellBuchanan], all you need is for your screwdriver to
slip, while tightening a wire to a bus-connector, to see
some risk. MY screwdriver slipped once inside a main
circuit-breaker box, and there were major sparks flying,
and a
melted-tip screwdriver, as a result. |
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This is a really cool idea. You need to consider piggy-backing though, and isolating connections to avoid what [Vernon] is talking about. |
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Quirky.com might pick this one up if it isn't already in the works somewhere. |
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[ ] but leaning towards + : the extra wire is a royal pita. |
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(Properly done) you could add two dedicated types of boxes to the electrician's arsenal: one for simple wall outlets (3 buss + ground) and one for simple switches (3 buss + device-hot + ground), perhaps another with 2 device-hots, for 2-phase DPST switches (this last one could handle all 3 types) |
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But you'd have to go back to the existing method for multi-gizmo boxes with more than one switch or more than one pair of outlets or a couple switches and an outlet, et cetera. |
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//without isolating the circuit// ah, another graduate of the Darwin School of DIY. |
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//[MaxwellBuchanan], all you need is for your
screwdriver to slip, while tightening a wire to a bus-
connector, to see some risk. // |
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The power will (should) be off while you're installing
the backbox, shirley? |
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This is actually a good idea - the fascia could just plug into connectors on the backbox and then be screwed down for security. |
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[FlyingToaster], I don't see why any type of wall outlet couldn't be used with this idea, so long as the fascia-to-backbox interface is compatible. If the two are simply connected by a fly-lead then there's no problem. However, I'd prefer to see an insulated plug/socket design so that the fascia can be installed or swapped out without first isolating the circuit. This should be no more hazardous than unplugging an appliance from an outlet. As [Max] points out, of course the power will be off during installation of the backbox itself. |
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//As [Max] points out, of course the power will be off during installation// - I have a feeling that professional electricians generally don't turn the power off unless they absolutely have to. The electrician who cut into our house's mains supply and wired in a 50A spur upstream of our consumer unit (fusebox) certainly didn't turn the power off first. |
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OK, yeah, somehow I forgot about the individually
switchable circuits for a house or office. The main breaker
box, however, often cannot be turned off arbitrarily (with
various circuits that MUST stay on) --and sometimes not at
all (no switch!), short of external shutdown of the entire
place. |
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[EL] Your raisin debtor for the post is to facilitate initial inspection on an entirely new build home. All well and good: assuming the electrician was competent and didn't cut corners, everything's fine. |
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But the next guy won't be an electrician: he'll just be somebody who wants an extra outlet for his TV, and he might hook it up without a chassis ground, or connect another hot to the common buss (which will blow up the TV but a desklamp would probably continue to work). Maybe the guy after that's a smartass and has just a one conductor cable and runs the common to a waterpipe. |
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If the problem is that tripping a breaker kills power to the entire room, including all outlets and lights, then it wasn't installed properly in the first place. |
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I don't see the problems here. |
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Installing the backbox would not be fundamentally
different from how it is done now: usually, the power
will be off at the time. A confident electrician might
work on the live system, in which case there's the
potential for accidents under either system; the
worst that should happen, in that case, is that he
trips the circuit breaker. |
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The only difference is that the huge rats-nest
junction is moved from the back of the socket/switch
to a terminal block inside the backbox. If anything,
this new system is safer: a misplaced screwdriver is
more likely (in the new system) to short between live
and earth, thereby tripping the breaker; in contrast,
a screwdriver-slip when wiring a regular socket might
leave the electrician as the only path between live
and earth (which then makes the sensitivity of the
RCD the only safety margin). |
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I'm not a qualified electrician, but I've installed
plenty of domestic wiring and I'd prefer the new
system to the old. |
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