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Posted by rpseguin on February 29, 2008, 3:38 pm
> |> | I'm just renting the house, which, by the way, doesn't have any
> |> | grounded outlets other than a couple of GFIs in the bathrooms.
> |> | The landlord did put 3 prong grounded receptacles in, even though
> |> | there's no ground wires in any of them.
> |>
> |> They don't make very many 2-prong ungrounded GFCI receptacles, even
> |> though such things would work and can even do a self-test without a
> |> ground wire.
> |
> | True. But to clarify: three prong GFCI receptacles that aren't grounded
> | are legal. Ungrounded three prong outlets _downstream_ of a GFCI are
> | also legal (as a retrofit), as long as you use the stickers saying
> | "ungrounded outlet" on them.
>
> How about one of those grounded plug adapters ... the kind where you have
> 3 holes on one end to plug in a grounded plug, and only 2 prongs on the
> other end to plug into a legacy 2-hole no-ground outlet ... that integrates
> GFCI protection as part of the adapter? I've seen GFCI cord sets, but only
> with a grounded plug. How about with an ungrounded plug?
The GFCIs look grounded to my tester. I haven't bothered to open
them up and look if there is a ground wire in there.
What I was trying to say is that all of the "normal" (non-GFCI) 3
prong outlets are just hot and neutral with no ground wire in there.
Landlord did the cheap thing, although I don't know of any easy and
inexpensive way to retrofit a ground in to a lot of outlets (say 20+).
As for my sub-panel and 3 phase panel things, I've just ordered a 500'
spool of #1 aluminum wire. It is _WAY_ less expensive than copper. I
will be certain to read up and make certain that I bond everything
correctly, use anti-corrosion goo and make certain all connections
are torqued down properly. The RPC and all of the machine loads will
be made using some copper THHN that I already have.
I've acquired a Cutler Hammer 3BR1224L125 125 amp 3 phase circuit
breaker load center panel and now I need to find some CH BR3xx plug/
stab-in breakers. 3 pole breakers are pricey new!
Anybody have some Cutler Hammer compatible breakers like these:
BR360
BR350
BR340
BR330
BR320
BR315
BR310
Thanks!
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Posted by Chris Lewis on March 3, 2008, 1:09 pm
> |>
> |> | I'm just renting the house, which, by the way, doesn't have any
> |> | grounded outlets other than a couple of GFIs in the bathrooms.
> |> | The landlord did put 3 prong grounded receptacles in, even though
> |> | there's no ground wires in any of them.
> |>
> |> They don't make very many 2-prong ungrounded GFCI receptacles, even
> |> though such things would work and can even do a self-test without a
> |> ground wire.
> |
> | True. But to clarify: three prong GFCI receptacles that aren't grounded
> | are legal. Ungrounded three prong outlets _downstream_ of a GFCI are
> | also legal (as a retrofit), as long as you use the stickers saying
> | "ungrounded outlet" on them.
> How about one of those grounded plug adapters ... the kind where you have
> 3 holes on one end to plug in a grounded plug, and only 2 prongs on the
> other end to plug into a legacy 2-hole no-ground outlet ... that integrates
> GFCI protection as part of the adapter? I've seen GFCI cord sets, but only
> with a grounded plug. How about with an ungrounded plug?
I'm not absolutely certain of the full nuances[+] of "plug connected device"
w.r.t. CEC or NEC, but strictly speaking I don't think NEC or CEC
applies in this case.
_However_, UL and CSA do. In particular, 2 two pin to 3 socket
adapter (without GFCI) will not pass CSA, and is illegal to offer
for sale in Canada. I do not believe such a device will pass UL
either, but UL doesn't have power-of-law as CSA (or legislatively
equivalent) does in Canada.
Conversely, if it has non-fraudulent UL or CSA markings on it,
it will be legal unless overruled by local ordinance.
[+] I'm meaning edge-cases here. 2->3 plug adapters that simply
make the third pin connect via pigtail to the outlet cover screw
are illegal and covered by both NEC and CEC I believe. As the ground
wire is screwed on, I think they're considered "permanent wiring".
Or something. I dunno for sure. They're certainly illegal in Canada
because they won't be granted CSA approval.
--
Chris Lewis,
Age and Treachery will Triumph over Youth and Skill
It's not just anyone who gets a Starship Cruiser class named after them.
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Posted by Lew Hartswick on February 27, 2008, 2:48 pm
rpseguin wrote:
> Ok.
> Thanks for everybody's help in the earlier thread.
> The 20HP rotary phase converter is working, but I now need to place it
> in the garage, about 70+ feet wiring run distance from the main
> breaker panel.
>
> Given the cost of copper wire these days, my inclination is to run
> just the two hots to the panel and to put a grounding rod close up to
> the garage and run a local ground to it.
> I see no reason to run a neutral line from the panel (the machines are
> all 3 phase).
>
> I know that I could run a ground line to the panel AND run a local
> grounding rod, but is it a bad idea to just do a local ground?
>
> What gage wire for a 20HP RPC, but the main/biggest load/machine will
> be a 10HP spindle and a couple of 2HP machines, never all at the same
> time? ($ signs get much bigger with the wire gage/diameter :-)
>
> Anybody near San Jose, CA have a spool of #4 or larger gage for
> cheap? :-)
>
> Thanks in advance!
Put the converter right near the entrance panel so the highest
current only has to run the short distance. Then run smaller
wire to the remote 3 phase loads. Requires an additional lead
but the lower current req. should work out a lot cheaper.
Now as to "remotely developed grounds" This was legal when
we did a bunch of "cabins in the woods" supplied from a main
lodge back quite a few years ago (I havent checked the code
since). We ran the power with two direct burrial wires and
installed a standard grounding rod at each cabin. This was all
code compliant (at that time).
...lew...
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Posted by Robert Swinney on February 27, 2008, 3:10 pm
Lew sez:
"Put the converter right near the entrance panel so the highest
current only has to run the short distance. Then run smaller
wire to the remote 3 phase loads. Requires an additional lead
but the lower current req. should work out a lot cheaper."
Not a good idea and not even remotely close to any "code". A RPC consists of
one or more idler and
load motors. The combination comprises a sort of electrical network. Complex
circulating currents
flow between the idler and load. It is not like there is a "generator" side and
a "load" side. The
same current circulates throughout the network; wiring should be sized
accordingly.
Bob Swinney
rpseguin wrote:
> Ok.
> Thanks for everybody's help in the earlier thread.
> The 20HP rotary phase converter is working, but I now need to place it
> in the garage, about 70+ feet wiring run distance from the main
> breaker panel.
>
> Given the cost of copper wire these days, my inclination is to run
> just the two hots to the panel and to put a grounding rod close up to
> the garage and run a local ground to it.
> I see no reason to run a neutral line from the panel (the machines are
> all 3 phase).
>
> I know that I could run a ground line to the panel AND run a local
> grounding rod, but is it a bad idea to just do a local ground?
>
> What gage wire for a 20HP RPC, but the main/biggest load/machine will
> be a 10HP spindle and a couple of 2HP machines, never all at the same
> time? ($ signs get much bigger with the wire gage/diameter :-)
>
> Anybody near San Jose, CA have a spool of #4 or larger gage for
> cheap? :-)
>
> Thanks in advance!
Now as to "remotely developed grounds" This was legal when
we did a bunch of "cabins in the woods" supplied from a main
lodge back quite a few years ago (I havent checked the code
since). We ran the power with two direct burrial wires and
installed a standard grounding rod at each cabin. This was all
code compliant (at that time).
...lew...
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Posted by Chris Lewis on February 27, 2008, 4:02 pm
> I know that I could run a ground line to the panel AND run a local
> grounding rod, but is it a bad idea to just do a local ground?
Yes, for the reasons expressed by others.
> What gage wire for a 20HP RPC, but the main/biggest load/machine will
> be a 10HP spindle and a couple of 2HP machines, never all at the same
> time? ($ signs get much bigger with the wire gage/diameter :-)
Remember that there are losses in the RPC. A 10HP spindle actually
loaded to 10HP (as opposed to an unloaded 10HP motor) is going to
present something more like 12-13HP on the RPC. So, you're going to
have to factor in 20-30% losses.
Secondly, yeah, wire is expensive. You may wish to consider
using aluminum instead. Done correctly (to-code connectors and
conductive grease for the application), it's just as safe, to-code,
and a lot cheaper.
When I installed the 100A subpanel to my detached garage (100'
of burial), I saved something near $300 by using aluminum instead
of copper, and the inspector was perfectly happy with it - despite
catching the electrician forgetting the grease on the subpanel end... ;-).
--
Chris Lewis,
Age and Treachery will Triumph over Youth and Skill
It's not just anyone who gets a Starship Cruiser class named after them.
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Page 3 of 5 < 1 2 3 > last >>
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