Benefits of power monitoring

[dsurber]

I just had a new PV system installed. 26 SunPower E19/240AC panels with integrated micro-inverters. When the installation of the PV system was complete I installed a ECM-1240 to monitor the actual production, as opposed to what the SunPower PV Manager and PG&E said were produced.

When I completed installing the ECM-1240 I got pretty strange numbers for the PV system. 26 panels is two strings of 13 panels producing about 12A on each leg of the two 240V circuits. Or rather it should be. I was seeing 21A on each leg of one circuit and 3A on the other. After much checking, testing, swapping leads around, etc I finally decided that either the micro-CTs were broken or there was something wrong with PV system.

I climbed up on the roof and it quickly became obvious what had happened. The installers had put 23 panels on one circuit and 3 on the other. This was an easy mistake to make, just swapping two wires, but not an acceptable one. The installer was back this morning and swapped the wires. Now I see 12A on each leg as expected.

So the ECM-1240 enabled me to catch and get corrected a potentially serious and expensive error. Paid for itself already. I've got another ECM-1240 still in the box. That will go on the main panel so I can verify PG&E's net metering. Not much reason to trust them either.

Douglas

[Teken]

I just had a new PV system installed. 26 SunPower E19/240AC panels with integrated micro-inverters. When the installation of the PV system was complete I installed a ECM-1240 to monitor the actual production, as opposed to what the SunPower PV Manager and PG&E said were produced.

When I completed installing the ECM-1240 I got pretty strange numbers for the PV system. 26 panels is two strings of 13 panels producing about 12A on each leg of the two 240V circuits. Or rather it should be. I was seeing 21A on each leg of one circuit and 3A on the other. After much checking, testing, swapping leads around, etc I finally decided that either the micro-CTs were broken or there was something wrong with PV system.

I climbed up on the roof and it quickly became obvious what had happened. The installers had put 23 panels on one circuit and 3 on the other. This was an easy mistake to make, just swapping two wires, but not an acceptable one. The installer was back this morning and swapped the wires. Now I see 12A on each leg as expected.

So the ECM-1240 enabled me to catch and get corrected a potentially serious and expensive error. Paid for itself already. I've got another ECM-1240 still in the box. That will go on the main panel so I can verify PG&E's net metering. Not much reason to trust them either.

Douglas

Douglas,

Great story and happy to hear it was resolved before anything bad happens.

Teken . . .