[Noisebridge-discuss] Computer Equipment in an old home?

Wed Jul 10 07:37:06 UTC 2013

Everyone is right that you might not even be pulling too much current
as-is, and it's cheaper to measure it than to add outlets.  In commercial
buildings at least, the fire department will tell you to not daisy chain
power strips, but you could fix that by getting a (UL approved) power strip
with a zillion (OK, 24)
outlets<http://www.amazon.com/Multiple-Outlet-Strip-w-Surge/dp/B00BHJCOSO/>.

I searched pretty extensively for evidence that old "knob and tube" wiring
was more dangerous than modern romex or wire in conduit, and couldn't find
anything except hearsay.

Two dangerous things are to cover it with (thermal) insulation (making it
prone to overheating) or to splice in new wire (incorrectly?).  I recall
finding something in the 2011 Electric
Code<http://www.amazon.com/Wiring-Simplified-Based-National-Electrical/dp/0971977976>that
said not to splice new wiring into knob and tube.

I've found it pretty easy to run new circuits from a panel, and as stated
above, fuses are reliable, safe technology as long as you don't bypass
them.  Code in SF (deltas from NEC 2007
here<http://archive.org/stream/gov.ca.sf.electrical/ca_sf_electrical_djvu.txt>
--
thanks, Archive.org!) doesn't require conduit, only Romex protected from
physical damage, and the biggest part of the work is crawling around
drilling holes and fishing the wire through.  I can't remember if it is a
requirement, but I keep my new romex and fixtures at least a foot from old
knob-and-tube once it leaves the panel area.

If there isn't room in the existing panel for new circuits, it is a
slightly bigger deal, but it's often cheapest to leave the existing panel
in place and add either a new panel or a sub-panel if the existing panel
has the capacity for a sub-panel (you may have to poach one of the existing
circuits and then feed it from

Once you have the wire installed, the outlet itself is pretty easy, they
make "new work" electrical boxes that are easy to install in drywall and
possible to install in lath-and-plaster.  (In drywall, with a drywall
saw<http://www.amazon.com/Stanley-20-556-6-Inch-FatMax-Jab/dp/B00005QVQH>,
cutting a hole is trivial.)  I usually install GFCI outlets, but if there's
no water anywhere near, a regular grounded outlet is fine.

For adding outlets, you're supposed to get a permit.  Last time I got a
permit for homeowner electrical work, it was about $45 and the inspector
was super helpful -- neither of us wanted to burn down the building.

Good Luck!
Dennis

On Tue, Jul 9, 2013 at 9:24 PM, Martin Bogomolni <martinbogo at gmail.com>wrote:

> I second the "replace the wiring" strategy.
>
> In one of the older victorians near Alamo Square, I helped a friend
> rewire the house using molded conduit in various rooms.   We also
> replaced the mains panel with a new one that had breakers (rather than
> glass fuses).
>
> It's not a trivial project, but it can be a relatively straightforward
> one.   Cost of materials and wiring for that project was ~$1200.
>
> -M
>
>
>
> On Tue, Jul 9, 2013 at 5:49 PM, Adrian Chadd <adrian.chadd at gmail.com>
> wrote:
> > ... turn-on current.
> >
> > TThe rush of turn-on current on a strip of electronics is not negligible.
> >
> > I'd also be surprised if ye olde house wiring is actually safe at
> > drawing 15A. You may find it's actually not safe to drive it at that
> > for very long.
> >
> > Combine that with all the myriad ways that these things are hooked up
> > behind the scenes - American houses seem have this habit of having
> > separate wiring for lights-that-terminate-on-wall-sockets versus the
> > occasional high-powered wall socket for something more than a light.
> > So it can all be quite deceptive. Your light circuit may not really
> > terminate a full 15A, let alone the higher rush when all your devices
> > turn on.
> >
> > Add in all the possible damage and failure cases with that wire, with
> > say weather and other environmental effects, and there's quite a lot
> > of potential "wtf?" going on that a fuse just won't tell you about.
> > And that's the kind of thing that can start fires and/or kill people
> > in other creative ways.
> >
> > Circuit breakers can detect and cut off these transient current
> > rushes. Fuses in mains wiring tend not to. I'd personally upgrade
> > everything to circuit breakers. If you start having some intermittent
> > circuit breaker resets, you can be sure you've done something stupid
> > or there's some transient dodgy wiring somewhere.
> >
> >
> >
> > -adrian
> > (I don't fuck around when it comes to mains electricity.)
> >
> > On 9 July 2013 17:40, Jake <jake at spaz.org> wrote:
> >> Hi Brian,
> >>
> >> I agree with what Gopi says - use a kill-a-watt to measure how much
> power
> >> you're using if you're afraid of overloading the wiring.
> >>
> >> but instead of that, you can simply get a power strip and plug
> everything
> >> into that.  A power strip has its own circuit breaker (15 amps) and that
> >> will trip before you blow a fuse.
> >>
> >> If your whole room is running from an extension cord from somewhere
> else,
> >> use a power strip (with its own circuit breaker - they all have one)
> where
> >> that extension cord plugs in.  You can also use a GFCI adaptor like
> this:
> >>
> >> http://www.amazon.com/GFCI-Outlet-Adapters-Single-Adapter/dp/B001OE3JHC
> >>
> >> That will get you a lot of protection.  If you take too much power in
> your
> >> room, you might pop the breaker in a power strip, or you might blow a
> fuse,
> >> but it shouldn't cause a problem otherwise.
> >>
> >> The thing is, most modern electronics don't use very much power.  You
> can
> >> have ten desktop computers and LCD monitors on one 15 amp circuit (1500
> >> watts total).  A cellphone charger is up to 5 watts - you can have 300
> of
> >> those!
> >>
> >> All this goes out the window if you try a toaster, electric oven, or
> space
> >> heater.  Forget it.  Also those big hot halogen lamps use a lot of
> power.
> >> But you can read the labels and do the math.
> >>
> >> If you want to preserve the wiring you have and keep it from messing up,
> >> just don't mess with it or allow things to flex.  The solid wires in the
> >> walls are not meant to move, they are stiff.  So if an outlet is loose
> and
> >> flops around, either tune it up or plug a power strip into it and screw
> the
> >> cord of the power strip to the wall, so it doesn't move things around.
> >>
> >> The fuses in your fuse box are fine.  This technology is very reliable,
> >> moreso than many circuit breakers!  A fuse is very unlikely to fail to
> fail,
> >> if you know what i mean, which means it will protect you.  Of course if
> a
> >> fuse has a penny stuck under it (someone tried to save the cost of a new
> >> fuse) then there is no protection.  The screw-in fuses were designed to
> >> allow you to put a lightbulb in place of a fuse to diagnose shorts.
> When the
> >> bulb stopped lighting up, there was no more current draw and you could
> >> install a new fuse.
> >>
> >> long story short, it's not the number of things you have, it's the total
> >> power draw, which will be limited by the fuse and any power strips on
> the
> >> way.  And don't let that old wiring move around or it might break.
> >>
> >> -jake
> >>
> >>
> >>
> >> Brian Perez wrote:
> >> Hey all, since SF has a lot of old buildings I'm sure someone could
> help me
> >> with this problem I'm facing.  I have an old home (circa 1930s) and all
> the
> >> wiring is the old copper cloth-covered kind and there's BARELY an
> outlet in
> >> the house.  My room has no outlet; my power is pulled through the
> window to
> >> the back room and up to the light socket.  BAD, I know.
> >>
> >> Being the tech guy I am I'm starting to run out of sockets with the
> >> extensions I have.  There's basically three surge protectors daisy
> changed
> >> to power everything in my room.
> >>
> >> What are my options to make this more secure and safe? (And potentially
> add
> >> more sockets)
> >>
> >> Thanks!
> >> Brian
> >>
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