Residental metering 1

[drax]

Is there an easy way to rig up a circuit for a building to indicate power consumption from the outside meter? Could I use metering CT's? I would like to see the cost of the power consumption by a display that reacts like the outside meter?

 

[jbartos]

Suggestions:
1. CTs are often used for services sized 400A and up on a low voltage power distribution system.
2. PTs will have to be added on any medium voltage distribution system, e.g. 4160V.
3. Once you obtain current and voltage suitable for any power/energy signal processing, it will just depend on your preferences regarding metering/revenue meters, manufacturer, price you will be willing to pay, etc.
4. Visit

http://www.thomasregister.com

and type "Meters: Electric, watt hour" under Product / Service that will return six companies to inquire about the product further.

 

[wbd]

I don't understand what you're trying to do. Why not just read the kWh from the existing meter?

Depending on the voltage, you may need potential transformers also and I don't know what the currents are but if you need CT's they should be meter quality.

As far as the meter, there are a host of electronic packages available, it depends on how much info you need. If you are going to the expense of PT's & CT's, you might as well want to look at power factor, peak demand, harmonics, etc.

 

[busbar]

Are you speaking of the ability to remotely read information from an electric-utility-owned watthour meter? It is possible that the meter owner could furnish a connection to internal dry contacts that change state in proportion to energy use. Typically you would then have to provide equipment to analyze the pulse train. It’s unlikely that they would do this free-of-charge for a residential application, though.

Outside of this, metering components from someone like hialeahmeter.com could potentially be installed by a qualified electrician. Figure a bare-minimum starting material cost of $200.

You might do an internet search for ‘submetering’ or ‘electric submetering.’

 

[Gene1203]

Your question is a bit vague. Do you want to countercheck the reading from the utility meter? If this is the case, you have these to consider: 1)incoming mains 2)main disconnecting means (CB panel, disconnect switch) 3)the nature of construction of 1) & 2).

You will be installing your own separate metering equipment. This will be dependent on these 3 considerations and of course your budget. You do not need to hardwire the utility meter - this will be against the utility company rules and besides, utility meters are sealed or tamper-proof.

There are a number of metering types from the bulky ones to digital ones. As to what type depends on the 1), above - size of incoming mains, 2)main disconnecting means or panel - where to mount the CT's and/or PT's and what size in amperes for the CT ratio, 3)the construction/installation of 1) & 2) to determine where you will mount the meter itself and the parameters you wanted to monitor.

As for a meter where you want to directly read the COST of energy consumption, I'm not quite sure if there is a stand-alone unit of this type. There are units that read almost all parameters including THD's - but they are only part of a power management system (usually PC based) which is used in large installations such as commercial/high-rise buildings, etc.

For your comfort, as-built drawings with ratings are far better to discuss with. You may consult an electrical engineer friend with a hard copy of your existing installation. Also, you may give us further information with details you feel necessary.

 

[drax]

Thanks for everyones help on a sort of stupid question. What I'm trying to do is set up a digital display inside of the house that will convert the Kwh to real dollars, live. I know it sounds stupid but my power bill is crazy and I would like to see real time the cost or approximate. I know I could read the meter but it is out of sight and out of mind. I was thinking that I could use a pic chip for the algorathim for dollar coversion but what do I do for input from the meter or panel?

Thanks,
Mark

 

[busbar]

Ask your utility if they will provide you with "KYZ meter pulses." This is a set of dry contacts in their meter that change state proportional to energy use. With those, it’s possible that your controller/display gizmo could look at the pulse rate and do the desired calcs.

 

[don01]

hi drax
go with busbar on this one. most utility meters have volt free contact which will pulse so many times per unit consumed. (water steam elec,gas etc). run this into you r "gyzmo" and magic!! an indicator.

An alternative suggestion if the utility wants too much $$$$.
try getting a cheap ammeter and ct. get your friendly sparky mate to put the ct in your board and rescale the meter in say $ or cents.
The instalation is single phase the volts are relatively fixed and the pf may drift a bit but you want to know when the bill is going off the planet not cahse down 10% true.
Total cost this idea say $50 Aus ($25 US) excluding family sparky.

Let us know how it goes
Don

ps Imentioned it the other day in another thread. A recent survey here (Australia) indicated that about 30% of the domestic power bill is from appliances in "standby mode".TVs computers phone thingos just have a look ~ its scary really

 

[Dan76]

don01 gets my vote for best application of the K.I.S.S. concept. (Keep It Simple Silly, NOT the Band.)
Plus everyone should have a friendly sparky mate!
Knowing a good welder and machinist helps too.

-Dan76