[Noisebridge-discuss] Fwd: Power to the peeple

[meredith scheff]

Heya Noisebridge,
This here is my pal Joshua. He's a super cool cat putting a hot tub in his
back yard, and needs a little electrical knowledge. Can anyone help?
His email is joshua at nowhereville.org, But I'll foward answers here, too.
m


Right on.

So the story is I got a 6' redwood hot tub for nothing. I'm getting a
control pack and heater for about the same. Which is good, because nothing
is about how much I have. But I have a dream. And it involves hot water.
I've gotten the tub, and assembled it, truing some beams, etc etc. I've
verified that with water it swells up and (mostly) seals; I've learned from
a boatbuilder friend how to pay and caulk wood, etc, which has been fun. I'm
about to run the suction joints and cap them off and actually fill it and
see if it holds water, or more likely, how much it leaks. Ahem.

So what I have to do is run 220 to my back yard. It's about 70' total, the
first half of which is in a garage w/ exposed wooden beams, the latter half
of which I will trench in a yard. Intervening is about 10' of concrete, not
sure how to cross that yet and stay within code for max turn radius/etc.

I figure I will drop in a 50A 220V circuit into my current box, run it to an
elbow at the back edge of the garage (hole already exists),  then put it in
some type of water-resist flex conduit and run it around and bury it,
putting in a breaker box at the back. Build a little cover for the guts of
the spa. Etc.

I have questions I figure a knowledgeable electrickal-person can answer. If
you can tell me anything, I'd be really delighted.

1 - I have 100A service, with 2x20A and 2x15A 120 already run. Can I put a
50A circuit into this box? The -total- of the breakers would then be over
100 (120), but as I read the code this is okay; in the same way as I can
plug in more than 15A of lights onto a 15A circuit, just not turn them all
on at once. The circuits are not in heavy use; we don't even have a
microwave. If not, I guess I need to get the main panel upgraded. Not
trivial I think, ugh.

2 - Should I put a ground in the back at the sub panel I put in for the tub?
Or use the ground all the way back through the main panel?

My other questions are mechanical - how to trench, where to mount a sub
panel, how to run the cable in the garage, and especially how to get it over
the concrete in the back. And code-related - 18" trench, I think, other
misc.


On 8 Nov, 2010, at 22:16 , meredith scheff wrote:

run the questions by me, and if I don't know, I'll pass them on to the NB
list.
M

On Mon, Nov 8, 2010 at 9:53 PM, Joshua Marker <joshua at nowhereville.org>wrote:

>        Hey, do you know about electricity? Like, at the high voltages? I
> need to run a 220 line and I have some questions - am concerned about both
> code and safety.
>
>        I also have a new hot tub controller that has a 12V line for lights
> and am thinking about what I could do. Arduinos are $33!
>
> --
> If God had meant for us to be naked, we'd have been born that way.
>       -- Mark Twain
>
>


-- 
doing stuff and making things
---
"The function of all art ... is an extension of the function of the visual
brain, to acquire knowledge; ...artists are, in a sense, neurologists who
study the capacities of the visual brain with techniques that are unique to
them. ." -Semir Zeki


 --
Virgo: (Aug. 23--Sept. 22)
One of your greatest problems is your inability to ignore oversimplified,
arbitrary, and potentially unsound advice from dubious sources.




-- 
doing stuff and making things
---
"The function of all art ... is an extension of the function of the visual
brain, to acquire knowledge; ...artists are, in a sense, neurologists who
study the capacities of the visual brain with techniques that are unique to
them. ." -Semir Zeki
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