Powerblaster - How to clamp CTs to 4 main lines?

[sp2pac]

I have Tesla solar with a Tesla Inverter and no Powerwall. I was like others and did not get a powerblaster installed when they first came to install the panels. So at PTO last month I looked at my app and I could only see production but not usage. After doing some research on the this forum I found out that I needed a powerblaster installed in order to see usage. I called customer support and they said they no longer provide them. I was very disappointed. Then about a week later Tesla had to come back to make some adjustments to the panels. I asked the employee if they could install a powerblaster for me since I couldnt see usage. I thought he would say it's discontinued, but surprisingly he said sure and pulled out a powerblaster from his truck!

We took a look at the box together and he said it can't be installed because there was no room for the CTs to go around the wires coming in from the meter. In addition, I had 4 main cables coming in from the meter instead of 2 and he had not seen that before. He said a work around would be to get an additional 2 CTs and splice the wires in order to get all 4 readings. The problem was that he couldn't clamp the CTs onto the cables since they are so close together and the cables run toward the back of the box so there is no room. I asked if he would just hook up the power for the powerblaster but just leave the 2 CTs unclamped while I figure out what to do. He obliged and installed the powerblaster by connecting it to one of the circuits for power and just left the CTs unclamped ready to go . He did not give me 2 additional CTs.

So my question is how can I hook this up to make it work so that I can see usage? Are there any workarounds? Has anyone seen 4 main lines coming from the meter? Also I've read in the forums about Neurio, is that the same as the powerblaster? FYI the pictures are before he put the powerblaster in there.

 

[miimura]

The installer is right. I don't see any good way to put CTs on those main lines. I'm sure the Powerblaster could be configured to read 4 CTs all as Grid, but I don't see that you can mechanically get the standard CTs around those wires unless there is space behind the bus bars.

Be very careful, those wires are hot at all times unless you pull the meter or there is a grid outage.

 

[arnolddeleon]

There is theoretical way assuming certain things are true:

There is only one bus (e.g. the parallel breakers are feeding the same bus)
We assume the resistance through the main breakers are practically the same
You can fit a CT around the top red one and bottom black one

If I'm remembering my E&M correctly the amount of current flowing through parallel conductors should be equal. So the CT's will pick up half of your current flow. Now you just need the software to scale double it.

There is also a way to do it but it would almost certainly break the listing of the panel, replace the lines feeding the main breakers with longer wires. That's what they did when a line side/supply side tap installed for my Solar City install 12 or so years ago. The lucky bonus was I able to put a large CT around the pairs of conductors.

Finally you can find a compatible CT that is like this:

Rogowski Coil Flexible Current Transformers – AcuCT Flex Series

Accuenergy’s Rogowski coil flexible current transformers are available in a variety of sizes and input ranges. Measure AC current with high accuracy.

www.accuenergy.com

 

[sp2pac]

There is theoretical way assuming certain things are true:

There is only one bus (e.g. the parallel breakers are feeding the same bus)
We assume the resistance through the main breakers are practically the same
You can fit a CT around the top red one and bottom black one

If I'm remembering my E&M correctly the amount of current flowing through parallel conductors should be equal. So the CT's will pick up half of your current flow. Now you just need the software to scale double it.

There is also a way to do it but it would almost certainly break the listing of the panel, replace the lines feeding the main breakers with longer wires. That's what they did when a line side/supply side tap installed for my Solar City install 12 or so years ago. The lucky bonus was I able to put a large CT around the pairs of conductors.

Finally you can find a compatible CT that is like this:

Rogowski Coil Flexible Current Transformers – AcuCT Flex Series

Accuenergy’s Rogowski coil flexible current transformers are available in a variety of sizes and input ranges. Measure AC current with high accuracy.

www.accuenergy.com

So if I was able to get longer cables installed for the 4 lines, can I just attach the CTs to the top red and bottom black and it would work or would I need to get 2 additional CTs in order to get a correct reading? Sorry I dont know electrical much, I appreciate the feedback.

 

[arnolddeleon]

So if I was able to get longer cables installed for the 4 lines, can I just attach the CTs to the top red and bottom black and it would work or would I need to get 2 additional CTs in order to get a correct reading? Sorry I dont know electrical much, I appreciate the feedback.

You would only get half the value if did only for the top and bottom (one red/one black). You will either need the system to double for it you, get for 4 CTs or get two wires in each CT (same phase/color in each CT). If you are able to replace the wires then more than likely you would do it in such way that that have one CT covering both red wires and the another CT the blacks. This requires an electrician who really knows what they are doing. It will require either a temporary service disconnection, probably by pulling the main meter.

If your goal is to simply know your consumption without necessarily being integrated with the Tesla app then you might want to consider a couple of products from Emporia Energy:

This would allow you to "read" your PG&E utility meter roughly every 10 seconds

Wireless Energy Monitor - Emporia: Revolutionizing Home Energy

Learn how the Emporia Vue Utility Connect enhances energy management in your home by connecting to ZigBee®-enabled AMI smart meters for real-time monitoring and savings.

www.emporiaenergy.com

Or their energy monitor with Rogowoski coils:

Vue Energy Monitors - Emporia: Revolutionizing Home Energy

Turn insights into savings. Connect an Emporia Vue Energy Monitor directly to your circuits to automate, manage, and control your home’s energy.

www.emporiaenergy.com

I don't have any experience with their products. I've just found them as I research power monitoring options.

 

[miimura]

So if I was able to get longer cables installed for the 4 lines, can I just attach the CTs to the top red and bottom black and it would work or would I need to get 2 additional CTs in order to get a correct reading? Sorry I dont know electrical much, I appreciate the feedback.

If you got the meter pulled and those 4 wires re-done, you could route them so that the two reds were pulled together with one CT around both reds, then another CT around the two blacks. That is the simplest way.

However, I don't know what the rules are for pulling the meter and having the utility come back out to put it back and re-seal it.

 

[albertm3]

Hi,
I have the exact setup. I have 4 wires, 2 reds, and 2 blacks wire running from the left side of the meter to the right side. Then the 4 wires goes into a 200A breaker. The installers was very good, and nice. I took them almost 1.4 hours to install the CTs.

Initially, they tried to find way to go behind it. But the wires are very thick, and it needs 4 CTs. It doesn't have room to get the hand behind. More importantly, those wires are hot. It's very dangerous situation. At the end, they have to pull the meter out. Once they pull the meter, then they can take out the 200 Amp breaker. 4 CTs are stagger offset one another.

Because they pull the meter without telling PGE, the utility came within 10 mins after they pull the meter out. After some explanation, PGE gave us a new security tie. Then we're good to go.

It was a difficult job, but it's doable.

Good luck. If I get around to take some picture, I will post it.

 

[sp2pac]

If you got the meter pulled and those 4 wires re-done, you could route them so that the two reds were pulled together with one CT around both reds, then another CT around the two blacks. That is the simplest way.

However, I don't know what the rules are for pulling the meter and having the utility come back out to put it back and re-seal it.

I'm not sure the 2 wires would fit inside 1 CT. Seems like the wires would be too big for the CT to be able to close. Also not sure how the utility would respond if I pulled the meter? Would they fine me?

 

[sp2pac]

Hi,
I have the exact setup. I have 4 wires, 2 reds, and 2 blacks wire running from the left side of the meter to the right side. Then the 4 wires goes into a 200A breaker. The installers was very good, and nice. I took them almost 1.4 hours to install the CTs.

Initially, they tried to find way to go behind it. But the wires are very thick, and it needs 4 CTs. It doesn't have room to get the hand behind. More importantly, those wires are hot. It's very dangerous situation. At the end, they have to pull the meter out. Once they pull the meter, then they can take out the 200 Amp breaker. 4 CTs are stagger offset one another.

Because they pull the meter without telling PGE, the utility came within 10 mins after they pull the meter out. After some explanation, PGE gave us a new security tie. Then we're good to go.

It was a difficult job, but it's doable.

Good luck. If I get around to take some picture, I will post it.

You're right we do have the exact same setup and I'm glad you were able to get it working, gives me some hope. When you say installers, do you mean Tesla installers or a 3rd party electrician? I'm assuming you have a powerblaster, how did you get 4 CTs to connect to it since it only comes with 2 CTs and there's no extra plugs for 2 more? Did the installers splice the wires on one of the CTs and add another CT to it?

Did you get fined or anything for pulling the meter? I live in SoCal and have Edison, not sure how they would react if I pulled the meter.

 

[BGbreeder]

Trust me. You do not want to pull the meter yourself. Google arc-flash. video

If this important to you, get an electrician to do it.

Yes, you can get fined, sometimes a lot, but it is really a life safety issue with huge risks. Death being common, as are blindness and burns.

I am not an electrician and don't play one TV either.

 

[sp2pac]

Trust me. You do not want to pull the meter yourself. Google arc-flash. video

If this important to you, get an electrician to do it.

Yes, you can get fined, sometimes a lot, but it is really a life safety issue with huge risks. Death being common, as are blindness and burns.

I am not an electrician and don't play one TV either.

Yea I agree, I wont be doing any of this myself. I'm happy to get an electrician but just want to see if it's even possible first before I go that route. Thanks for you input.

 

[albertm3]

You're right we do have the exact same setup and I'm glad you were able to get it working, gives me some hope. When you say installers, do you mean Tesla installers or a 3rd party electrician? I'm assuming you have a powerblaster, how did you get 4 CTs to connect to it since it only comes with 2 CTs and there's no extra plugs for 2 more? Did the installers splice the wires on one of the CTs and add another CT to it?

Did you get fined or anything for pulling the meter? I live in SoCal and have Edison, not sure how they would react if I pulled the meter.

It was done by Tesla. The powerblaster has only two inputs, one for red and one for black. The CT is just an amperage sensor. Each CT has only enough space for one wire. Tesla installer bring in two more CTs, and splice two of them together. Then you have two set, each of them has 2 CTs. Because it powerblaster just measuring current, so it's OK to splice them in parallel.

Since I'm not the one pulling the meter, I didn't get fined by doing it. Good luck, it's doable, but it's just more work. The easy way out is just saying "not enough space". Typical home owner would walk away.

When they install it, make sure all the CT are put in with the right direction. It can't be flip around.

 

[Patrick66]

Just install one red and one black, and have the values set to be scaled 2x. Anything else requires the utility to come out while you have an electrician modify the wiring.

 

[sp2pac]

Just install one red and one black, and have the values set to be scaled 2x. Anything else requires the utility to come out while you have an electrician modify the wiring.

I dont think I'll be able to even get the CTs around the cables since there is no room back there, but if I was, how can I scale the values 2x?

 

[sp2pac]

Quick update: After multiple calls with Tesla last week complaining about not getting the powerblaster installed, to my surprise they got a Telsa electrician to come out and install the Neurio gen 2. He said the powerblaster I had is not compatible with the Tesla inverter (not sure if that is true). But he came and did what the others on this forum recommended and pulled the meter, then reached back to the 4 main lines and pulled them a little bit so there was more slack to attach the CTs. On the Neurio gen 2 there are 4 ports for CTs so no splicing was necessary. He opened up another Neurio box to get the 2 additional CTs. Because the Neurio would not fit, he added another box to store it. See pic below for the 4 CTs at the top. It took about an hour but he was able to get it all setup and now I can see usage on the Tesla app.

So thats the good news. The bad news is that I feel like the usage is not reading correctly while there is solar generation. For example, at night when solar is off, I'm usually using 0.5-1kW without using any major appliances. But then in the morning when solar starts ramping up at around 11am to about 3kW, my usage starts going up to about 1.5-1.8kW even though I'm not using any extra electricity. As solar generation ramps up even more the percentage of usage follows it and is usually around 50-60% even though I'm not using more electricity or not even home. So at 6kW of solar, I'm usually at 3-3.5 kW of usage. Has anyone else had this problem as well? At night when solar stops generating at around 7:30pm then I get a correct reading. Also when I check my meter, it will show the correct amount going back to the grid and not tie to the app data. Any thoughts on this?

 

[nomis_nehc]

Not helpful, but as a comment, this is exactly the reason why they stopped doing it. Ran into too many customers where installation of it is just unfeasible. Can it be done, possibly, but the process of it is not worthwhile to the company at all in terms of labor.

 

[miimura]

The solar bleeding into the Grid consumption is a common configuration problem. Tesla is able to fix it remotely when a Powerwall Gateway is involved and they should be able to do the same with a Tesla Inverter plus Neurio.

 

[sp2pac]

The solar bleeding into the Grid consumption is a common configuration problem. Tesla is able to fix it remotely when a Powerwall Gateway is involved and they should be able to do the same with a Tesla Inverter plus Neurio.

It's really hit or miss for me. Yesterday for example it was showing the correct energy usage throughout the day usually around 1kW. Then today it jumps back up to a percentage of production (50-60%). It's really weird. I guess I'll contact Tesla to see if this can be fixed on their end as you mentioned.