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KWh Meter for detached Garage???

Mike Purcell

Member
Joined
Apr 22, 2012
Messages
5
Location
Halifax, NS
Hey Guys;

My detached garage has been finished for years and I run a small woodshop in it. But lately I have been told I need to provide the lovely tax folks with actual power usage, no more guessing a percentage of the household used.

So what I need is a meter that I can install inside or beside my panel in the garage that measures ALL the power consumed in the building. I picked up a meter than said it did it but it only read the 240 volt power usage and it detected nothing being consumed on either 120v leg.

I think technically I need a 1 phase split voltage meter but can't seem to find one that anyone knows will work for sure. Some that maybe...'might' work but the electrical shops won't allow returns so its a gamble. Seems most just say a new power company meter but then I'd have to pay commercial power rates and meter charges for what's little more than a hobby. Surely somebody has added a KWh meter (preferably) re-settable to their garage to monitor power usage. Any suggestions??

Thanks
Mike
 
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klassenl

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Joined
Feb 20, 2016
Messages
715
Location
Southern Alberta
If it's for tax purposes why not get a contractor to install a check meter for you. This cost to install will be a tax write off.

This shouldn't be a big job and probably take less than had a day.
 
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Git

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Joined
May 18, 2008
Messages
6,894
Location
S Cal
It's pretty common when people lease a solar array that the company adds a second meter to keep track of things. Usually they are side by side, like you described

I did a quick search and found this meter for $45

https://www.gordonelectricsupply.co...Milbank+Cl200-D+200A+Watt-Hour+Meter&lsi=true

attachment.php
 

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wyliesdiesels

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Joined
Aug 14, 2012
Messages
20,073
Location
Modesto, CA
Hey Guys;

My detached garage has been finished for years and I run a small woodshop in it. But lately I have been told I need to provide the lovely tax folks with actual power usage, no more guessing a percentage of the household used.

So what I need is a meter that I can install inside or beside my panel in the garage that measures ALL the power consumed in the building. I picked up a meter than said it did it but it only read the 240 volt power usage and it detected nothing being consumed on either 120v leg.

Wow with all the responses already I cant believe not one person explained the following.

You said it read the 240v power but nothing on either 120v leg? That doesnt make any sense because the 2 120v legs literally make 240v and thats how the meter measured the current on the 2 120v legs.

You need a better understanding of how a kilowatt hour meter works and how a split phase multi-wire circuit works(all single phase 120/240v services are multiwire branch circuits). The neutral in a 120/240v split phase service only carries the difference in current between the 2 120v hot legs.

Go take a look at a 4-jaw(single phase 240v) meter pan and see how it connects to the meter. there is only connections for the 2 120v legs. The neutral is passed on through.

here is an example:

https://www.amazon.com/dp/B07GB7423F/?tag=atomicindus08-20

Every single-phase meter for a split-phase/single phase 120v/240v service only meters the 2 120v legs @ 240v. No need to meter the neutral because it would just measure the difference in current between the 2 legs. A neutral on a split-phase single phase 120/240v service or a 208Y/120v or 480Y/277v service ONLY carries the current difference between the legs.

So if you metered the neutral, your power consumption totals would be way off.

I think technically I need a 1 phase split voltage meter but can't seem to find one that anyone knows will work for sure. Some that maybe...'might' work but the electrical shops won't allow returns so its a gamble. Seems most just say a new power company meter but then I'd have to pay commercial power rates and meter charges for what's little more than a hobby. Surely somebody has added a KWh meter (preferably) re-settable to their garage to monitor power usage. Any suggestions??

Thanks
Mike

no, the meter you need, you already have if its for split phase service.

If you want something re-settable then you will need a digital meter.

What style meter do you have? mechanical?
 
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OP
M

Mike Purcell

Member
Joined
Apr 22, 2012
Messages
5
Location
Halifax, NS
When I hooked it up it did read power used when I turned on the 220v dust collector but would not read the 110v compressor. Just showed zero power being used despite the compressor running.

I disconnected it thinking it wasn't working. but maybe I'll take another look at it. When I emailed the company that sold it they straight up said it would measure 110 or 220 but it would not measure a split combined power.

Now that I think about it it used a trapping coil on the neutral and then a wire pierces each of the hots so it should be measuring the power used on each leg of the 220.

I don't want an exterior meter housing either. I am looking for an interior box mountable. I did look at the EKM stuff but truthfully was just having a hard time finding the right one as so many of them seemed to be 120 or 240 but non seemed to state that the did both at the same time.

I'm away this week but I'll hook that meter up again this weekend and see if maybe it was user error, but its a pretty install.

Thanks
Mike
 
OP
M

Mike Purcell

Member
Joined
Apr 22, 2012
Messages
5
Location
Halifax, NS
I took a look at the EKM page at the setup in the power Meter System package is exactly what I am looking to do and EKM seems a LOT safer than the one I have. I'll drop them an email ASAP.

Thanks again
Mike
 

wyliesdiesels

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Joined
Aug 14, 2012
Messages
20,073
Location
Modesto, CA
When I hooked it up it did read power used when I turned on the 220v dust collector but would not read the 110v compressor. Just showed zero power being used despite the compressor running.

I disconnected it thinking it wasn't working. but maybe I'll take another look at it. When I emailed the company that sold it they straight up said it would measure 110 or 220 but it would not measure a split combined power.

Now that I think about it it used a trapping coil on the neutral and then a wire pierces each of the hots so it should be measuring the power used on each leg of the 220.

I don't want an exterior meter housing either. I am looking for an interior box mountable. I did look at the EKM stuff but truthfully was just having a hard time finding the right one as so many of them seemed to be 120 or 240 but non seemed to state that the did both at the same time.

I'm away this week but I'll hook that meter up again this weekend and see if maybe it was user error, but its a pretty install.

Thanks
Mike

what brand and model meter do you have?

Power company single phase meters dont even connect to the neutral.

Are you sure the meter you have says to hookup to the neutral?

I'm guessing you only meter the neutral if you have 120v loads only.
 
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MattT

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Joined
Feb 20, 2010
Messages
3,201
Now that I think about it it used a trapping coil on the neutral and then a wire pierces each of the hots so it should be measuring the power used on each leg of the 220.

What the heck did you buy:headscrat

I don't want an exterior meter housing either. I am looking for an interior box mountable.

You can mount a meter base indoors if you want to go that route.
 
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rlitman

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Oct 18, 2010
Messages
24,663
Location
Long Island
yeah i shouldve been more clear. I was speaking of single phase meters.



a 9s is for 3 phase


Right. I’m not familiar with other meter pans, but I’d think there’s a comparable single phase CT type?

Edit: found it, 4s.
 
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wyliesdiesels

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Joined
Aug 14, 2012
Messages
20,073
Location
Modesto, CA
Right. I’m not familiar with other meter pans, but I’d think there’s a comparable single phase CT type?

Edit: found it, 4s.

yeah thats a 6 jaw. pretty rare. only see it on a house with large 400a service(and not the 320/400a service)

the 4 jaw used by most homes does not connect to neutral.
 

Tracs

Well-known member
Joined
Feb 1, 2015
Messages
569
Location
Manitoba, Canada
Hey Guys;

My detached garage has been finished for years and I run a small woodshop in it. But lately I have been told I need to provide the lovely tax folks with actual power usage, no more guessing a percentage of the household used.

So what I need is a meter that I can install inside or beside my panel in the garage that measures ALL the power consumed in the building. I picked up a meter than said it did it but it only read the 240 volt power usage and it detected nothing being consumed on either 120v leg.

I think technically I need a 1 phase split voltage meter but can't seem to find one that anyone knows will work for sure. Some that maybe...'might' work but the electrical shops won't allow returns so its a gamble. Seems most just say a new power company meter but then I'd have to pay commercial power rates and meter charges for what's little more than a hobby. Surely somebody has added a KWh meter (preferably) re-settable to their garage to monitor power usage. Any suggestions??

Thanks
Mike

No help from me. Is the woodshop an actual business that you claim on your taxes? Is that why they want to know how much you are claiming?
 

MBfreak

MEMBER EMERITUS
Joined
Dec 10, 2010
Messages
2,301
Location
Linkoping , Sweden
Electrical engineering questions using written explanations only tend to confuse, even persons with very good knowledge. I for one.

A simple sketch in this case, showing
Source including "phases", neutral and protective earth with voltages added
Wiring to meter
Nameplate diagram of meter
Loads connected after meter, between phases and phase to neutral

A kWh will not work if the voltage inputs are not correct

Ola
 

Norcal

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Joined
Mar 16, 2008
Messages
13,769
The simplest way and pretty cheap way too is to install a 4 jaw meter can and get a KWH meter, because of the switch to “smart” meters there should be a flood of used ones on the market at a reasonable price.
 

dcg9381

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Joined
Jun 20, 2018
Messages
11,918
Location
Austin, TX
Surprised no one has suggested this - why not use one of the inductive systems that are available? They cost a little more than a $45 meter, but you won't have to re-route or re-wire anything.

IE: Sense Energy Monitor
 

yatg

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Joined
Aug 16, 2019
Messages
2,836
Location
Southern Oregon
I meter my computer rack for tax purposes. Here's a diagram of how to wire a standard 240V meter for 120V metering. Pay close attention to the neutral connection to the back of the meter.
 

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