Which we weren't, but anyway... I've just been reading about how insurance claims for power surges are down this year, despite the year having been the worst ever for load shedding. 

This is attributed to insurers insisting on SPDs. They suggest at least a class 2 SPD, installed in the DB. 

The article goes on to say that SPDs have a limited useful life and should be tested every couple of years. 

Which is where I go huh? My understanding is that SPDs that go in the DB are sacrificial. A big surge comes along, SPD takes the hit and saves the day, but that SPD is now not good for much. 

Am I wrong? My SPDs have little indicators on them that show when they have been triggered and must be replaced. 

How then does one test SPDs without sacrificing them? 

Yours non-technically. 

I have to say spd is getting exspensive as we're I stay they show red almost every month as we get hit constantly by surges .  In the end I install an voltage and amp protector before the spd .

So far all looks good let's hope it stays this way . 

They normally show green when good red is replace .

Don't think there a way to test it with out going red . 

I often ride along with a friend that does solar installation and often we having to replace these things as he installs them as standard installation regardless of insurance or not .

A very interesting writeup about SPD's. 

Informative chat from Roland on exactly this subject. He lost two Inverters whilst away due to a suspected overvoltage.
 

 

Type II SPDs have a varistor that becomes conductive above a certain voltage.  It basically shorts the live to neutral if the voltage is exceeded.  Depending on the size and duration of the surge, the device could survive many incidents if none of them are big enough to fry the SPD.  However, since the SPD is not in line with the loads, if the SPD fails only your protection goes away - your power to your loads is not cut.

Since you may not know that there has been an incident, you need to check the SPDs regularly.  Most have some sort of indicator of whether they are still working.

Type I SPDs use a gas capsule, which again can survive many small incidents but would need replacement of the gas capsule for a bigger strike.  I'm reasonably sure these are inline with loads, so if the SPD fails you have no power.  Needs verification however.

So I have two DBs for the PV system. One for DC (I assume this is the line from the panels) one for AC. Both have surge protection. 

Here is the DC board. 

And here is the protection on the AC board

Edited December 8, 20231 yr by Bobster.

39 minutes ago, Paulcupine said:

Type II SPDs have a varistor that becomes conductive above a certain voltage.  It basically shorts the live to neutral if the voltage is exceeded.  Depending on the size and duration of the surge, the device could survive many incidents if none of them are big enough to fry the SPD.  However, since the SPD is not in line with the loads, if the SPD fails only your protection goes away - your power to your loads is not cut.

Since you may not know that there has been an incident, you need to check the SPDs regularly.  Most have some sort of indicator of whether they are still working.

Ah thanks. So they are actually in parallel to the loads.

1 hour ago, Paulcupine said:

Type I SPDs use a gas capsule, which again can survive many small incidents but would need replacement of the gas capsule for a bigger strike.  I'm reasonably sure these are inline with loads, so if the SPD fails you have no power.  Needs verification however.

Not necessarily, for example, the DEHNGuard basic above, has a gas arrestor in series with an MOV to reduce leakage.

Also, the indicator is supposed to turn red before the MOV fails, which also shorts the input to ground mechanically, tripping the upstream breaker.

A Scotsman (living on the Isle of Man) known as 'Big Clive' has done a few teardowns on SPDs for his youtube channel that some might find interesting:

https://www.youtube.com/@bigclivedotcom/search?query=spd

Pretty informative, essential viewing if you find yourself tempted by any 'bargains'. 😱

Here in the UK it's not mandatory to fit them if you have a risk assessment performed that demonstrates that you don't have to, but we charge more for doing the risk assessment than the cost of just fitting the SPD. 😆

6 hours ago, HedgeSlammer said:

you find yourself tempted by any 'bargains'. 😱

Now the question is what brands are good quality SPDs? Suggestions?

1 hour ago, FixAMess said:

Now the question is what brands are good quality SPDs? Suggestions?

Just follow the installs of @Steve87 and @TaliaB and others and see what they use copycat

Edited December 9, 20231 yr by Scorp007

For Dc applications i use Noark SPD'S and Dc Mcb's.

 

For Ac applications i use Schneider SPD's.

5 hours ago, FixAMess said:

Now the question is what brands are good quality SPDs? Suggestions?

I've no idea what's available in .za, but I tend to go with the Wylex units with a 100A DP isolator, as they're pleasant to fit and replacement modules are likely to be available in the future, but mainly because the box looks nice and I'm not paying for it. 🙂

Other than that, MK or BG ('British General')...  I think choosing a reputable, established supplier is more important than brand, as there are new (cheaper) devices coming to market all the time and a good supplier isn't going to want to damage their reputation by selling junk.

4 hours ago, Scorp007 said:

Just follow the installs of @Steve87 and @TaliaB and others and see what they use copycat

By all means like i said preferably Noark and Scneider they are more expensive but you can't compromise on safety.

Where areas are prone to lighting strikes( Drakensberg) i use ABB Class 5 surge arrestors on the AC side. Below example of the ABB. Short Circuit breaking capacity 100KA.

https://www.online.elio.co.za/product/ovr-t2-t3-1n-20-275-p-qs/?utm_source=Google+Shopping&utm_medium=cpc&utm_campaign=GoogleFeed&gclid=CjwKCAiAvdCrBhBREiwAX6-6Use5-N0KYXkDEOON5971CuwZvaF6aJkGcq0y0OMHGKByeKHwA9n9YxoCjy0QAvD_BwE

 

Edited December 9, 20231 yr by TaliaB

Is one of tha ABB jobs required for each sub db as well or just 1 on the main incoming line?

So the ABB is good for AC side, what must be used for DC side?

 

2 hours ago, FixAMess said:

Is one of tha ABB jobs required for each sub db as well or just 1 on the main incoming line?

So the ABB is good for AC side, what must be used for DC side?

 

 

8 hours ago, TaliaB said:

For Dc applications i use Noark SPD'S and Dc Mcb's.

Many of the suppliers suggest a type 2 at sub-boards if they are over 10m away on the basis the internal cables can pick up induced surges due to ground strike or and direct strike.

I wish I knew whey there are two AC SPDs in my installation. The DC is easy - because of the labelling. One per string. So a body can understand that.

But on the AC side? One to protect the inverter, and thus the backed up circuits, and one for the non-essentials?

The guy who did the installation has moved on and I no longer have a way to contact him.

NB! I am not going to take any opinions expressed here to my insurer and say "you see! An electrician said...". Besides which they will want a signed off certificate, not hearsay from me.

Edited December 10, 20231 yr by Bobster.

I find the SPD topic fascinating.

So I have two 2pole DC SPD's which I plan to replace due to wrong rated size in my DCDB where the four DC fuses are and two 2p DCCB's as I have 2in 2out from PV. I installed a 16mm earthing cable going from the Earth bus bar to an earthing rod outside about 4m away and 6mm earth from SPD's to earth bus which shares earth on the inverter. I am told I need to add another earth wire and rods for the ACDB on the right as I cannot use the same earth bus, wire and rods for the AC side. Is this correct?

I have also included a single pole SPD on the AC out from the inverter connected to dedicated plug and light in the garage. I was told it isn't necessary. Is this correct?

I then have a bit of confusion; my panels on the roof are also bonded to another set of earthing rods and 6mm earth cable, in addition to running to the DCDB in the garage. It is joined to this second earth along the way. The 6mm earth from the panels is running inside the same conduit as the + PV feed line.

I don't understand why + is with earth cable in same conduit?

Why the PV earth has been joined to the earth which was added for additional house protection and bonded to the Mains DB earth with 2pole AC SPD. 

Somewhere along the PV conduits  there is a crossover or twist which I think is inducing voltage into one of my PV DC lines, but this I will look at another time as I get low DC voltage through the night when there really shouldn't be any production.

I have more queations but I'll open a topic for that when I get a chance.

I'll try to add an image of the layout and design later on.