Can anyone confirm the size of the AC input and output breakers for a Sunsynk 50kw unit? When I look up the install guide, I'm seeing figures of 200A passthrough and 240A breaker recommended.

Our installer initially put in 60A breakers for both input and output but of course this kept tripping. He claimed this was to protect the inverter. We convinced him this is too low and he wanted to go to 80A but I questioned that as it would limit our passthrough power. He said he would ask the importer (Herholdts) and they came back saying we should use 100-125A breakers. This doesn't agree with the Sunsynk info I can find online - so is the online info wrong or is this installer and importer wrong? I'd love to know what other installations are using?

@JaseZA Off the cuff, ask yourself this: who offers you the warranty on your inverter, the importer, the installer or equipment manufacturer? That is who you should listen to and conform to. Others will only offer recommendations. But experts on this site will also be a good guide.

Edited October 31, 20241 yr by Moffat

Did the inverter not come with a manual in the box, one that's including installation instructions? What does that booklet say?

Check your Eskom feed MCB, and size it similar on the input. If you are hoping to use higher power in the day on your essential loads (Eskom + Solar + Battery), add Eskom MCB value to 83.4A, with a max of 200A.

By the way, beautiful machine, I'm jealous.😂

 

Edited October 31, 20241 yr by TimCam

2 hours ago, GreenFields said:

Did the inverter not come with a manual in the box, one that's including installation instructions? What does that booklet say?

Yeah, unfortunately I'm a bit late to the party here. This install was done a year back and I was asked to come give a second opinion after the issue with the tripping.

2 hours ago, TimCam said:

Check your Eskom feed MCB, and size it similar on the input. If you are hoping to use higher power in the day on your essential loads (Eskom + Solar + Battery), add Eskom MCB value to 83.4A, with a max of 200A.

By the way, beautiful machine, I'm jealous.😂

Thanks TimCam - that's exactly my thinking. We have 150A from Eskom currently and 50kwp solar with a 60kwh HV battery. I was asking for a 160A breaker to allow us to use Eskom plus solar when available. We're also hoping to drop the Eskom supply to 80A and use grid peak shaving to ensure we don't trip. Currently paying R15k/month to have 150A vs 80A prepaid with no monthly fees.

26 minutes ago, JaseZA said:

We're also hoping to drop the Eskom supply to 80A and use grid peak shaving to ensure we don't trip. Currently paying R15k/month to have 150A vs 80A prepaid with no monthly fees.

The cost of the pole and transformer is crazy high unless you're a large business. 😲

I hope you can still get 3 phase prepaid, maybe this Eskom page below is old and not updated?

 

 

11 hours ago, JaseZA said:

We have 150A from Eskom currently and 50kwp solar with a 60kwh HV battery. I was asking for a 160A breaker to allow us to use Eskom plus solar when available.

Technically, you are not allowed to increase the supply - if your eskom supply is 150A, then that is the maximum breaker you may install anywhere in the system. The solar is not allowed to supplement above that limit. (But nobody pays attention to that, so do whatever you want.)

Just remember that the work of the Breaker is to protect the cable and not the Inverter. No use to have a 120A breaker with a cable that cant handle the amps.

21 hours ago, JaseZA said:

Can anyone confirm the size of the AC input and output breakers for a Sunsynk 50kw unit? When I look up the install guide, I'm seeing figures of 200A passthrough and 240A breaker recommended.

Not sure about above comments as 50kw 3ph does not compute to 240A breaker.

The breaker size input and output for the specific 50kw inverter should be 83A x 1.25 = 103.75A closest standard breaker 100A. 

Not sure if adequate calculations was done initially before installing the inverter. A few very important questions?

1. What is the original utility 3 ph supply breaker.

2. What is the size of the 4 core supply cable entering the premises( point of supply).

3. Should the supply breaker be upgraded to 100A you should have a 25mm² 4 core armoured cable( SWA) from the utility supply point.

4. Is the original installer/ electrician qualified to work on 3ph supply systems as a normal IE can not supply the COC it needs to be signed off by a MIE or a electrical engineer as these factors could void the warranty.

I was just wondering 🧐 

 

Edited November 1, 20241 yr by Derek3

You should do calculations on your side otherwise you going to damage your inverter. if you go according to the manual that yo get with the inverter.

A 50Kw inverter is actually 3 x 16,66Kw single phase inverters. Your supply from your utility to inverter is a 100A 3p breaker and your return is a 80A 3p breaker.

I have done 5 x 50Kw systems and don't have any issues. if you install a 250A breaker as they say in the Manual you are going to damage your inverter, I find on a lot of re installs that the guys doesn't have any knowledge of how to do the correct calculations, even for a 5Kw or a 8Kw. if your a real installation electrician you will have the knowledge to do the calculations and not follow the manual that is wrong.