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Viewing 15 posts - 31 through 45 (of 94 total)
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  • in reply to: Usage not matching meter readings #8128 Report Abuse
    djwakelee
    Member

    The 200A clamps are for connection to single phase, split phase (aka 2-phase), and 3-phase mains (1-3 ports and clamps used depending on electrical service).  For the UK, you are 240V (50Hz) and single phase.  That would mean you would use a single 200A clamp for your combined mains power feed (before both meters).  You can’t use another 200A clamp (on the A/B/C ports) to measure a separate circuit, such as you are trying to do with heat and other loads.  That is where you would use the 1-16 ports and the 50A clamps.

    If you can’t place the single 200A clamp before the two meters (physically, etc), you can purchase a 3.5mm Y cable and combine (2) 200A clamps into the single A port.  That way you can get the combined reading for your domestic loads and heat, and clamp after those meters.  If you want to then know the individual power in each, that is where you would add the 50A clamps (connected to ports 1-16) and clamp those around the circuits you want to specifically monitor.

    After you make this change, you’ll probably want to re-setup the software as it is surely confused by seeing power on something other than the A port for a UK installation.  It is probably improperly assuming split-phase currently, if you are indeed using port B (which shouldn’t be being used for single phase).

    Hope that helps.

    • This reply was modified 5 months, 2 weeks ago by djwakelee.
    in reply to: Hardware idea: Vue Gen 2 with Ethernet #8112 Report Abuse
    djwakelee
    Member

    Agree this would be a welcome feature.  Note that this is typically not done on UL listed / NEC compliant energy monitoring products due to the fact they are designed to be placed inside the electrical panel.  Under a fault condition (such as chafed insulation in the Ethernet cabling, etc) a short circuit would electrify the lower voltage signalling circuits leaving the box – presenting a high voltage on the Ethernet cabling and end-device.  Because of such a scenario, it is generally not permissible by NEC to have low voltage wiring coexisting unchecked with AC mains voltage – and leaving the box.  Special physical partitioning is required to isolate the high and low voltage aspects, and this would not be present in a standard electrical panel.

    Some Ethernet energy monitors (like The-Energy-Detective) get around this by using power line communication and having the Ethernet gateway outside of the panel. But typical PLC challenges apply with that approach (interference, reliability).

    • This reply was modified 5 months, 3 weeks ago by djwakelee.
    • This reply was modified 5 months, 3 weeks ago by djwakelee.
    djwakelee
    Member

    For 3 phase, understand the Vue2 is only compatible with Y (Wye) type configuration with neutral.  If your 3 phase is Delta type or without neutral, it wouldn’t work properly.  The majority of people use the Vue2 with residential split phase 240V/120V in the US (and 240V single phase in other countries), in which case it correctly measures real power on all circuits.  3 phase commercial setups are not as popular, but are supposed to be supported if up to 415Y/240VAC Y type with nuetral.  Perhaps some other folks with that setup can chime in and report if they see in discrepancies in operation with 3 phase setups (as well as what country).

    You may want to verify your 3 phase hookup, and/or contact Emporia chat.  They don’t seem to monitor this forum as much as they used to.

    • This reply was modified 7 months, 1 week ago by djwakelee.
    djwakelee
    Member

    From Emporia chat…

    “we measure apparent and real power, and use real power on all circuits”

    The poster who theorized VA measurement on the 16 circuits did mention 3 phase – so maybe there is some bug there.  But with 120V/240V split phase in the US, I see accurate W (real power) for the 16 circuits and mains with mixed power factor loads – as confirmed by Emporia.

    djwakelee
    Member

    My experience is different.  I have all circuits monitored, and zero balance (or so).  At times there are plenty of inductive loads (AC compressor, pool pumps, forced air blower), which greatly exceed any 1.0 power factor devices.  The math always adds up with the individual circuits, balance, and mains – within that 2% tolerance.  If the circuits were only measuring apparent power (VA), things would be way off.

    The original Vue 1 only measured VA (apparent power), and was horribly inaccurate for non-resistive loads.  The Vue2 is spec’d to measure true power, and I have no reason to believe this is only on the mains.  My observations do not support that conclusion at all.

    Would like to hear from Emporia regarding this.

    in reply to: Total Usage A/B #8015 Report Abuse
    djwakelee
    Member

    In the amps view, you are seeing the total amps on each leg, but the circuits are not broken out per leg – just a big list.  So those shown can be on either leg.

    Know that the Amps feature is relatively new to the app, and has bugs.  It is also not really what it appears.  The Vue2 only sends real power to the cloud – the Amps values are just divided by an assumed 120V voltage.  Based on actual line voltage and type of load (resistive, capacitive, inductive), the reading may not match the actual amps flowing through the circuit (only if resistive load – and exactly 120V line voltage).  It also shows incorrect 2x current if you use a multiplier for single clamp 240V circuits.

    The Vue2 is an excellent and accurate power (W/kW) and energy meter (kWh), but presently missing things like real amps and power factor.  If you can switch to W view, that is how your energy company bills you, and that’s really where the device displays information correctly.

    • This reply was modified 7 months, 2 weeks ago by djwakelee.
    in reply to: Emporia Vue 2 showing 2x amperage #8010 Report Abuse
    djwakelee
    Member

    Known bug.  When you set a multiplier presently (such as single clamp 240V), the Amps reading is also doubled.

    Also, know that Amps value is presently manufactured – the Vue2 only sends real power to the cloud.  We don’t get to see real Amps draw – just the power divided by assumed 120V line voltage, which doesn’t take into account real/apparent power and phase angle for AC loads (resistive/capacitive/inductive).  So the Amps shown at present is not necessarily what you’d measure with a DVM clamp meter on that circuit.

    Emporia has promised an update handle 240V circuits better (and presumably fix this bug), but unknown when this is due now.

    • This reply was modified 7 months, 2 weeks ago by djwakelee.
    in reply to: Notifications by Peak Amp Draw #7988 Report Abuse
    djwakelee
    Member

    You can do this with the present notifications.  Add a new custom alert, and pick then ‘Mains’ circuit.  You can specify the kW you want to be notified of (can’t specify amps, but you can convert to kW).  So for your example of 65% for a 200A service, 200A x 240V = 48kW x 0.65 = 31.2kW.  You can spec an interval down to as low as 1 second.

    There is also a built-in notification alert for when you hit a peak for the month also.

    Also, you typically want to be looking at this in terms of power anyway.  The Vue2 is and energy/power meter (kW and kWh), and not really a good current meter (A).  Know that Emporia presently does not give you a true Amps value, it only records real power to the cloud.  The Amps value shown is manufactured – the true Amps value (with no relationship to power factor) is not shared.  This is a known limitation in their present implementation.  Requests have been made to indicate current (A), Apparent Power (VA), and power factor – but unclear if this will ever be implemented.

     

     

    in reply to: Uk installation – tripping RCD #7966 Report Abuse
    djwakelee
    Member

    I’m far from an expert on UK wiring, but it sounds like your RCD (residual current device) is the same concept as our GFCI’s (ground fault circuit interruptor) here in the US. Since the Emporia wiring doesn’t leave the electrical box, a connection through a special fault protection device like that is not needed – you’d normally just connect it to a standard circuit breaker. However, if the way your electrical box is setup there is an RCD upstream that protects all the other individual circuits in the box, then I understand why you have to would need to deal with this.

    Fundamentally, when connecting up through any fault protection device, you have to have all the current go through the same supply and return wiring that the device monitors. If the protection device sees a mismatch between the supply and return current of a certain amount, it trips. It sounds like you had the white wire go back to the RCD monitored neutral circuit, but the blue and red return elsewhere to an un-monitored neutral bar. Since there is current in those other wires (though small), your fancy RCD is not going to like that and think there is an actual fault.

    If you can post a photo it would probably help. But if you are installing Emporia on a new single pole circuit (dedicated circuit breaker), that would go to the black lead and all the other wires (white/blue/red) would go to where you connect your neutral return wires in the box. If you are installing a double pole breaker or fault protected breaker like an RCD (which switches 240V hot and potentially neutral), your hot would go to the black wire and all the other 3 wires go to the neutral output of the protection device.

    Hope that makes sense. If it makes it easier, for your 240V application, think of the Emporia black wire as the power feed (hot wire), and all the other wires (white/blue/red) as a single neutral. What’s really going on is the blue and red are the other ‘unused’ hot phases – they are not used in single phase applications and must be tied to neutral (white) so there is no induced voltage on them to confuse the system.

    • This reply was modified 8 months ago by djwakelee.
    in reply to: Combine 2 Circuit into a single reading? #7961 Report Abuse
    djwakelee
    Member

    In the setup you describe, you are measuring the combined current for each wire as accurate as possible.  But the voltage being used (for the power calculation) is actually just one of the 120V phases and not the correct 240V total.  Emporia doesn’t natively support 240V measurement – it doesn’t know you have a 240V circuit.  Likely only a small error if the 120V phases are similar in actual voltage, and the resistive load of the dryer heating elements makes phase angle (critical for power measurement) not come into play here.  In doing it this way, I believe if you switch to Amps view it will also show up as double the actual amount.

    in reply to: Combine 2 Circuit into a single reading? #7959 Report Abuse
    djwakelee
    Member

    Probably hard to measure precisely as there is enough variation clamp to clamp – Emporia only guarantees 2% (clamps and sensing).  If your 120V phases are the same voltages, yes – you will not see much error.  But nonetheless, there will be some if your phases aren’t balanced – even if small.  This will also depend on what loads you have, with resistive (like a hot water heater element) being less affected than older non-power factor corrected electronics, and inductive or capacitive loads.

    in reply to: Combine 2 Circuit into a single reading? #7956 Report Abuse
    djwakelee
    Member

    Yes, you can add the currents of the 120V or 240V circuits on different phases using the above method (route the other phase backwards through the same CT), but this does not yield a totally accurate power result.  To calculate power, Emporia (or any energy monitor) needs the current of the circuit (from the CT) and the voltage (from the 120/240V input).  It also figures out the phase shift between the current and voltage, which is necessary to calculate real power (W) and not apparent power (VA).  When you mix the two phases in the same CT, the voltage source of only one phase is referenced.  If your 120V legs are not split exactly (one high and one low), that will yield an error in the power calculated.

    Also, if you do this with 240V circuits, there is additional error since Emporia currently doesn’t deal well with 240V single clamps – we need to use the kludge multiplier.  And when you do that, the software just multiplies the one phase by 2x, instead of adding the voltage of both phases.  But that is a limitation with single clamp 240V for all circuits right now – not just if you try and combine them.

    • This reply was modified 8 months, 1 week ago by djwakelee.
    in reply to: Best Solutions for Two 200A Panels #7943 Report Abuse
    djwakelee
    Member

    Yes, what you summarized it all correct.  Just make sure when you connect the 2nd set of 200A CT’s in your main panel to the Y cable, you ensure they are on the same hot phase.  The red/black coloring on the associated wires downstream does not guarantee this – should confirm with a meter.  You should measure zero volts from the garage main conductor to the house main conductor.  If you measure 240V, you are on different phases – and don’t plug those 2 CT’s into the Y-cable.  Hope that makes sense, and if not comfortable with testing given lethal voltages, an electrician can certainly help.

    And yes, you need to do this independent of potentially getting a 2nd Vue2 for your garage setup.  Once you have the 2nd 200A CT’s and Y cables, all your math will be correct with the total power draw from the utility.  Any power not monitored by clamps in your main panel plus any power from the garage will show up as a ‘balance’ figure.

    • This reply was modified 8 months, 1 week ago by djwakelee.
    • This reply was modified 8 months, 1 week ago by djwakelee.
    in reply to: Best Solutions for Two 200A Panels #7939 Report Abuse
    djwakelee
    Member

    That’s interesting – how the disconnect for the other panel is in the main panel – though fed from different conductors in the meter box.

    Without going into the meter box and putting your mains clamps there (before the split), you can add a 3.5mm Y cable and connect another set of CTs to that 100A circuit (right above your existing 200A clamps).  Using the Y cable will parallel the CTs and add up your two mains feeds.  You must parallel the same hot phases for this to work.

    With the state of the Emporia software right now (doesn’t scale well with lots of circuits or Vue 2’s), you have two options.  You can treat your garage panel as a sub panel, and connect the mains clamps to the incoming feed as well as all your circuits.  Then you can nest the garage panel under the main panel in the software, and everything will total correctly.  Or…

    If you are preparing for the eventual unified circuit view (listing of all circuits for both Vue2’s together), you would not use the mains clamps on the 2nd Vue2 and just treat it standalone for now – using only the 50A CTs.  At least that is what Emporia advised me to do.  I have two Vues’2s in my main panel as I have many more than 16 circuits – basically same scenario as you but all in one panel.  Doing it this way, the ‘main’ Vue2 has all the math correct, but there will be a balance and you have to select the ‘secondary’ Vue2 to see those circuits.

    We have been promised a software update to have all the circuits combined/sorted in a single list over multiple Vue 2’s, but it seems to be dragging on.  Would be nice for Emporia to give an update on when combining multiple Vue2 circuits into a single list is planned for.

    • This reply was modified 8 months, 1 week ago by djwakelee.
    djwakelee
    Member

    Also, you may want to check the Solar Supplement guide.  It shows the two ways the solar is typically connected – and monitored with clamps…

    https://www.emporiaenergy.com/Gen%202%20Solar%20Supplement.pdf

Viewing 15 posts - 31 through 45 (of 94 total)