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New setup with 12 CTs installed currently - what hw config is the better choice?

Kindest,

I have just completed a switchboard reconfiguration and now have 12 circuits and clamps installed and ready to be put to use. I do not have any of the monitoring devices yet, but wanted to check with the community what would be the appropriate setup to go with.

Seems like 3 x EmonTX is a decent choice in the main switch board : https://guide.openenergymonitor.org/setup/emontx/ . That will give 12 circuits monitored.

For main unit it seems that emonPi or emonWeb is the two choices - would that be correct? The emonPi seems to be the “better” choice with the alu box and what not… would that be a correct assumption? Guess they both offer the same capability more or less, but it has the display, but also a “product finish” of sorts.

I also do have solar, which would be great to do as well, but that setup is separate in the back yard shed. Not thought about how to connect and monitor that besides what Fronius offers itself.

Anyhow - would greatly appreciate any tips and what not as to where to land with this… so can plan to get the main units and get this going.

As for the solar … I have the solar in the back yard shed on it’s own switchboard. That’s ~40-50m away from the main switchboard. Looking at https://guide.openenergymonitor.org/applications/solar-pv/ , how would I be able to connect C1:Grid in that configuration? Any thoughts?

Here’s a picture of the switchboard as it stands right now. Each number has it’s corresponding clamp…

Welcome, Jorgen, to OEM.

By “clamps”, might you mean current transformers? If you have nothing to connect them to, you MUST short-circuit the output connection of each before you energise the circuit. If you haven’t done that, you’re relying on them having an internal protection diode, and if that fails (or there isn’t one) you may well have destroyed or damaged each c.t.

I don’t recognise that.

All we’re able to offer at present is the emonTx or the emonTx Arduino Shield, so as you suggest, you need three units.

Apart from being a “base” to receive the data from the three emonTx’s, your emonPi will give you an extra two c.t. inputs and a voltage input - it’s effectively a 2-channel emonTx, emonPi and radio receiver all in one box. So unless you can use the 2 power measurements it gives you, there’s little point in having them.
Related to that: What’s the No.1 breaker, labelled “SUB”? And do you have a c.t. on the main incomer?

Can you get access to meaningful data from the solar inverter? And if so, can you get that onto your LAN, either by cable or WiFi?
If not, where is that connected into your house system? If you can access that infeed, you can monitor the current at that point. If not, what is between wherever you put the emonPi/emonBase and the back yard shed, in terms of obstructions to a UHF radio signal?

Ah… that would be interesting… I was referring to the > 100A max clip-on current sensor CT < as a clamp. Must admit that they have not been short circuited… clamped on by the electrician when putting the board up and the plugs labelled according to the circuit they were clamped on. Hoping that they’re not busted… have 4 extra clamps here that are not used, but kind of have to cross my fingers they’re then not busted… Sigh!

I don’t recognise that.

All we’re able to offer at present is the emonTx or the emonTx Arduino Shield, so as you suggest, you need three units.

Apart from being a “base” to receive the data from the three emonTx’s, your emonPi will give you an extra two c.t. inputs and a voltage input - it’s effectively a 2-channel emonTx, emonPi and radio receiver all in one box. So unless you can use the 2 power measurements it gives you, there’s little point in having them.

Ok. Got it… so it would probably make sense to have 3 x emonTX’s to send to a base, which would be inside. Perhaps a emonPi which could be used for the solar, but guessing that would be too far given that shed switchboard is 40-50m away.

Related to that: What’s the No.1 breaker, labelled “SUB”? And do you have a c.t. on the main incomer?

I think he missed that. The “Main switch grid supply” is the main incoming I believe. As for SUB, I believe that is for the sub board that is in the shed. So the shed has 4 circuits + solar and is connected with a fairly chunky power cable.

Can you get access to meaningful data from the solar inverter? And if so, can you get that onto your LAN, either by cable or WiFi?
If not, where is that connected into your house system? If you can access that infeed, you can monitor the current at that point. If not, what is between wherever you put the emonPi/emonBase and the back yard shed, in terms of obstructions to a UHF radio signal?
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Yep - there is a switch board in the shed that is connected to the main front of house switchboard with a fairly chunky cable to mitigate voltage loss as per regulation. Then in the shed there is the solar that is connected and that switch board also has 4 separate circuits to power the shed & it’s sections.

Could monitor that infeed, but that would be for all that’s used/generated in the shed (sorry - n00b here!). Hence to get the true generation I am guessing would have to connect that on the feed from the inverter to the switchboard there given it’s sort of a separate area to the front of house.

Now I wish I had taken an electricians license. :wink:

If those are the YHDC ones from the shop, then you should be OK, but I wouldn’t leave one on an energised circuit and not short it. As I wrote above, you’re depending on the protective diode inside.

To me, this is a clamp - busbar variety:
image

So that effectively rules out monitoring the shed feed at the main switchboard - unless of course you’re prepared to neglect the usage out there. What about the practicality of getting a radio signal from the shed - either WiFi or ISM band? 50 m isn’t silly if there’s a reasonably clear path, but if there’s another shed (metal), or a metal caravan or truck parked in the line of sight, or several thick walls, you may struggle. I’m not a fan of mains-borne Ethernet adapters, but that’s another possibility.

That doesn’t make too much sense. If that’s where your emonCMS runs, you’ve got to get data from the 3 emonTx’s out there, and the web pages back. If you have an emonBase in the house, the only reason you need the RPi in the shed is to get an Ethernet/WiFi output: you could have another emonTx out there and go serial to Ethernet to mains in the shed, and mains to Ethernet to router in the house; or have the WiFi enabled emonTx and WiFi to mains instead.

It does sound like you will want the emonBase in the house. It’s a Raspberry Pi with a fairly small module sitting on the GPIO connector, that sits no higher than the stacked USB sockets. You can look at it as an emonPi with no energy monitoring, display or box. It can easily go in a not very large plastic project box.

You could of course go belt & braces and have both emonPi in the shed and emonBase in the house, and cross-feed the data so that each gets a complete set of data and is a backup to the other. The fly in that ointment is SD cards tend to fail if you get a mains failure, so both could get damaged simultaneously (Sod’s Law).

[quote=“Robert.Wall, post:4, topic:15653, full:true”]

If those are the YHDC ones from the shop, then you should be OK, but I wouldn’t leave one on an energised circuit and not short it. As I wrote above, you’re depending on the protective diode inside.

To me, this is a clamp - busbar variety:
image

Aahh! Ok… got it… yeah, that’s a proper clamp… there you go when a n00b is trying to explain. :wink: But yes, they’re all from the shop.

If the advice is to short them - how is this done?

So that effectively rules out monitoring the shed feed at the main switchboard - unless of course you’re prepared to neglect the usage out there. What about the practicality of getting a radio signal from the shed - either WiFi or ISM band? 50 m isn’t silly if there’s a reasonably clear path, but if there’s another shed (metal), or a metal caravan or truck parked in the line of sight, or several thick walls, you may struggle. I’m not a fan of mains-borne Ethernet adapters, but that’s another possibility.

I have both wifi and switched ethernet out there, so have the option of hooking into existing network. The switched network is the same whereever on the property it is… and the wifi is a mesh wifi with the shed on a cat6 backhaul configured (Netgear Orbi). Seems to work well for all network requirements back there…

Is there a way then to use the existing network to hook in the solar / inverter usage of sorts?

[> quote=“jskogsta, post:3, topic:15653”]

Perhaps a emonPi which could be used for the solar
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That doesn’t make too much sense. If that’s where your emonCMS runs, you’ve got to get data from the 3 emonTx’s out there, and the web pages back. If you have an emonBase in the house, the only reason you need the RPi in the shed is to get an Ethernet/WiFi output: you could have another emonTx out there and go serial to Ethernet to mains in the shed, and mains to Ethernet to router in the house; or have the WiFi enabled emonTx and WiFi to mains instead.

Hmm… yeah, that makes sense… see there’s several options. As I mentioned above, I have network in the shed as well… just that where the mains board is, it is wifi only. Could stretch a cat5/6 cable there, but have not to date. But have both wifi + switched ethernet by the shed board + inverter…

It does sound like you will want the emonBase in the house. It’s a Raspberry Pi with a fairly small module sitting on the GPIO connector, that sits no higher than the stacked USB sockets. You can look at it as an emonPi with no energy monitoring, display or box. It can easily go in a not very large plastic project box.

Ah… ok… yeah, that makes sense… the emonBase in the house and then emonTX’s at the front + then I guess the question is the shed. Can a emonTX be used there for the solar/inverter monitoring? How does that get configured then in the emonTX or emonBase as a solar monitoring system? Sorry to ask, but never configured this setup before. Very handy with UNIX and shell and all of that, but not familiar with this system and don’t have the units to play with yet. Trying to figure out what to buy to then start coniguring it. :wink:

You could of course go belt & braces and have both emonPi in the shed and emonBase in the house, and cross-feed the data so that each gets a complete set of data and is a backup to the other. The fly in that ointment is SD cards tend to fail if you get a mains failure, so both could get damaged simultaneously (Sod’s Law).
[/quote]

Ah… yes, that could also work I guess. So if i understand it right, I just need to get the clamps in the right spots in the shed for the inverter monitoring… and it does not really matter whether that is emonTX or emonPi?

Can take off the covers to take a closer look at the switches & cables as to where I need things connected if that helps.

Greatly appreciated for the quick and detailed responses! Really looking forward to getting this up and running!

If the advice is to short them - how is this done?

You can simply twist some bare copper wire around the tip and sleeve of the plug. Switch the circuirt off first.

Sorry I can’t reply in detail, my laptop has died