Hi, I'm hoping someone can help me figure out the best way to install an
Emon kwh submeter to monitor electrical usage in my garage. I bought a house
with one attached garage and a second detached garage. I want to rent out
the house and use the detached garage. I intend to run a couple compressors
and use an arc welder, plus it has electric heat and A/C. Bottom line is
that I want to rebate the tenant for the electricity I use in the second
garage.

My main panel has a double 50-amp breaker that feeds the garage's sub-panel
(3 - 6ga in 3/4" rigid pipe). The sub-panel holds up to six breakers and 4
slots are filled with 1-30 amp dual and 2-20 amp breakers. I would like to
use the remaining 2 slots for the welder's breaker (50-amp dual).

The submeter is model 1000 for 2-line, 240v, 1-phase, 100 amp. The submeter
must have 2 power feeds + neutral and must be powered by the line(phase)
being monitored by the corresponding Current Transformers (CTs). The leads
for the CTs can be up to 2000 feet long.

I can think of several ways to install the meter :

1) I can pipe in the meter on the house side from the main panel, add 2
15-amp breakers, run 14ga power to the meter (with 1-amp inline fuses), run
the lines for the CTs to the main panel and install the CTs at the 50
breaker. Problem is, I want to be able to read the meter without going into
the house. I don't think the meter is rated for the outdoors. Also, I don't
want to tear up the family room to add the conduit or run it outside the
house (a lot of work depending on where I finally put the meter).

2) Install the meter in the garage. Take up the last 2 slots in the subpanel
with 2-15 amp breakers for the meter, install the Current Transformers in
the subpanel and run power and the CT leads to the meter (not good cause
then I loose the welder, but easiest). Or, I could upgrade the subpanel with
one that has room for more breakers (not good - more work).

I don't think it matters if I install the current transformers in the main
panel or the sub-panel. The current is the same in both places. Yes, the
voltage drops at the garage but I am billed for watts-used which is the
same(?). Probably not a big deal any way, even if it did affect the metering
accuracy (2% ???).

3) Run another pipe from the main panel to the garage - or replace the
existing 3/4" pipe (both very bad - a lot of work) - and run the 3
conductors that power the meter (14 ga) plus the 4 wires for the Current
Transformers (22 ga?) to the garage. Breakers would be in the main panel
inside the house . Is this an allowed run from the house to the garage?

OR...

4) If this is possible - Install the meter in the garage and tap off the
6-ga feeders coming in to the subpanel with 12-ga (with inline fuses - but
no dedicated breakers) - then run the taps to the meter (1 foot). Run the
lead wires for the CTs from the subpanel to the meter and install the CTs on
the feeder wires at the sub-panel. Is this possible/advisable? It's easiest,
it lets me read the meter from the garage, and I don't loose the welder or
need to replace the sub-panel.

Thanks for any help or information on which is the best route to go.

Regards,
John

Hey, if you can afford to buy a "Demon", the rest should be easy.If you
don't have a main breaker in the garage panel, you can only have six handles
worth or breakers, so, I'd get a bigger panel, install a 50 amp main, and
plenty of room for all the other stuff, plus more room inside to negotiate
the CT's



"John" wrote in message
. ..
Hi, I'm hoping someone can help me figure out the best way to install an
Emon kwh submeter to monitor electrical usage in my garage. I bought a
house
with one attached garage and a second detached garage. I want to rent out
the house and use the detached garage. I intend to run a couple
compressors
and use an arc welder, plus it has electric heat and A/C. Bottom line is
that I want to rebate the tenant for the electricity I use in the second
garage.

My main panel has a double 50-amp breaker that feeds the garage's
sub-panel
(3 - 6ga in 3/4" rigid pipe). The sub-panel holds up to six breakers and 4
slots are filled with 1-30 amp dual and 2-20 amp breakers. I would like to
use the remaining 2 slots for the welder's breaker (50-amp dual).

The submeter is model 1000 for 2-line, 240v, 1-phase, 100 amp. The
submeter
must have 2 power feeds + neutral and must be powered by the line(phase)
being monitored by the corresponding Current Transformers (CTs). The
leads
for the CTs can be up to 2000 feet long.

I can think of several ways to install the meter :

1) I can pipe in the meter on the house side from the main panel, add 2
15-amp breakers, run 14ga power to the meter (with 1-amp inline fuses),
run
the lines for the CTs to the main panel and install the CTs at the 50
breaker. Problem is, I want to be able to read the meter without going
into
the house. I don't think the meter is rated for the outdoors. Also, I
don't
want to tear up the family room to add the conduit or run it outside the
house (a lot of work depending on where I finally put the meter).

2) Install the meter in the garage. Take up the last 2 slots in the
subpanel
with 2-15 amp breakers for the meter, install the Current Transformers in
the subpanel and run power and the CT leads to the meter (not good cause
then I loose the welder, but easiest). Or, I could upgrade the subpanel
with
one that has room for more breakers (not good - more work).

I don't think it matters if I install the current transformers in the main
panel or the sub-panel. The current is the same in both places. Yes, the
voltage drops at the garage but I am billed for watts-used which is the
same(?). Probably not a big deal any way, even if it did affect the
metering
accuracy (2% ???).

3) Run another pipe from the main panel to the garage - or replace the
existing 3/4" pipe (both very bad - a lot of work) - and run the 3
conductors that power the meter (14 ga) plus the 4 wires for the Current
Transformers (22 ga?) to the garage. Breakers would be in the main panel
inside the house . Is this an allowed run from the house to the garage?

OR...

4) If this is possible - Install the meter in the garage and tap off the
6-ga feeders coming in to the subpanel with 12-ga (with inline fuses - but
no dedicated breakers) - then run the taps to the meter (1 foot). Run the
lead wires for the CTs from the subpanel to the meter and install the CTs
on
the feeder wires at the sub-panel. Is this possible/advisable? It's
easiest,
it lets me read the meter from the garage, and I don't loose the welder or
need to replace the sub-panel.

Thanks for any help or information on which is the best route to go.

Regards,
John