what device will regulate the voltage to a steady 230 v

[bony999]

Hello world of knowledge

I am trying to find a device that will regulate the incoming supply of power to my inverter to a constant 230V as the incoming mains ranges between 225 and 250.3V.

My main switch is an "MEM"  ELCB  (circa 1980)  rated to 240v  80 mA and I have a suspicion that it trips occasionally ( in wet and windy weather for some reason) as a result of the possibly unstable voltage being applied to it. My reasoning is that at 2.00am when the inverter switches to utility priority in order to chage the batteries from overnight cheap electricity it goes into line mode, the incoming voltage is usually at the peak end of 240 to 250 v and I wondered if the action of switching with the high voltage was what was tripping the ELCB.

I do not seem to have an isue when the weather is fine which also needs investigating but for the meantime perhaps if I was able to regulate the supply in to the inverter via something that took out the peaks at the point of switching it may just work. Of course the item would also need to keep the utput steady whilst absorbing the peak supplied to it.

My logic was to find something(transformer or other) that kept the voltage to 230 v input for the inverter irrespective of the voltage that was applied to the transformer/whatever device was available. The  limit into the inverter is 1.5 kw so it would not need to be too large I am thinking.

I have looked online to find something but without knowing exactly what is needed it is an issue to determine what t ask for.

If someone was able to assist in this I would be very grateful of the advice.

[Thunderdolt]

Back in the day we had to install Constant Voltage Transformers, in certain computer installations, that were transformer based, large, heavy and expensive.

A quick web search only came up with this. Give them a call, I'm sure someone will help you.

https://www.phdpowerhouse.co.za

Edited December 22, 2023 by Thunderdolt
punctuation

[jbroo]

Generally used in audio and music studio contexts, but a power conditioner may do the trick:

https://www.furmanpower.com/stable-power-regulation/

https://www.furmanpower.com/220-240-volt-region-pro-av-commercial/

[jbroo]

Also this: https://za.rs-online.com/web/p/power-conditioners/7079839

The current draw/passhrough limitation is likely to be an issue however.

[jbroo]

And finally maybe this: https://za.rs-online.com/web/p/power-conditioners/7079851

[Moffat]

My experience in East Africa (Burundi) was also similar with voltage fluctuations happening every 10-15seconds and to protect even Tvs and computer servers and backup drives had to buy an AC stabilizer such as this: https://www.ato.com/voltage-stabilizers. Saved me tonnes of headaches and costs on equipment replacements.

[Scorp007]

6 hours ago, bony999 said:

Hello world of knowledge

I am trying to find a device that will regulate the incoming supply of power to my inverter to a constant 230V as the incoming mains ranges between 225 and 250.3V.

My main switch is an "MEM"  ELCB  (circa 1980)  rated to 240v  80 mA and I have a suspicion that it trips occasionally ( in wet and windy weather for some reason) as a result of the possibly unstable voltage being applied to it. My reasoning is that at 2.00am when the inverter switches to utility priority in order to chage the batteries from overnight cheap electricity it goes into line mode, the incoming voltage is usually at the peak end of 240 to 250 v and I wondered if the action of switching with the high voltage was what was tripping the ELCB.

I do not seem to have an isue when the weather is fine which also needs investigating but for the meantime perhaps if I was able to regulate the supply in to the inverter via something that took out the peaks at the point of switching it may just work. Of course the item would also need to keep the utput steady whilst absorbing the peak supplied to it.

My logic was to find something(transformer or other) that kept the voltage to 230 v input for the inverter irrespective of the voltage that was applied to the transformer/whatever device was available. The  limit into the inverter is 1.5 kw so it would not need to be too large I am thinking.

I have looked online to find something but without knowing exactly what is needed it is an issue to determine what t ask for.

If someone was able to assist in this I would be very grateful of the advice.

Just a side note. There are many consumers with inverters that have a daily 250V and it does not seem to be a problem. The general rule for our grid code in Europe and ZA is 260V. At that level on line inverters could trip unless a higher setting is used. 

As per the link already provided you can get voltage stabilisers from about 500VA and up. Just bear in mind that you can hear the servo motor when it is adjusting and that can be seconds apart. Pricing is actually very reasonable for the functionality. 

Normally E/L operate only when the L and N current are not in balance. If the delta is over the specific value it should trip. 

Edited December 22, 2023 by Scorp007

[HedgeSlammer]

9 hours ago, bony999 said:

My main switch is an "MEM"  ELCB  (circa 1980)  rated to 240v  80 mA and I have a suspicion that it trips occasionally ( in wet and windy weather for some reason)

I'd suggest you look at the cause of the ELCB tripping before anything else.  It shouldn't trip whatever voltage fluctuations are thrown at it.

The ELCB (Earth Leakage Circuit Breaker, known elsewhere as a Residual Current Breaker, or RCD) will/should only trip if it detects a leakage of current to earth somewhere on your side of it. 

It does this by essentially measuring the current flowing in both the live and neutral conductors, and if it sees a difference (of over ~80mA, in your case), it trips.

It could be a number of things causing it to trip...

It may be faulty (it's done pretty well at 40+ years) and tripping at a very low leakage current, in which case, it needs replacing.

Or it could actually be working fine, it's just that there's already a small amount of earth leakage in the circuits throughout the house, which gets a little bit worse in wet weather... just worse enough to push the RCD over it's trigger threshold.

If any part of the house wiring is anywhere near as old as the RCD, I'd say this is most likely to be the cause.  A build up of dust and dirt behind any of the socket outlets or switches, or junction boxes, etc could easily create a low resistance path to earth - that gets worse when there's a bit of moisture in the air.

If you can find a competent electrician, they should be able to test the RCD for you, to establish whether it's working as it should. Then they'd hopefully do a 'whole house' insulation resistance test, which will highlight if there is any significant earth leakage - and if there is, start to identify which particular circuit(s) are the cause of the issue. 

If you have any circuits that run outside of the house (outside lighting, spurs off to a shed, etc), that might be a good place to start.  Look for signs of water ingress, failing rubber seals, that sort of thing.  Other likely culprits include water heaters, washing machines etc.

But do get that RCD checked - at 40+ years, it's done it's bit.  It might just save your life one day. 

[TaliaB]

4 hours ago, HedgeSlammer said:

I'd suggest you look at the cause of the ELCB tripping before anything else.  It shouldn't trip whatever voltage fluctuations are thrown at it.

The ELCB (Earth Leakage Circuit Breaker, known elsewhere as a Residual Current Breaker, or RCD) will/should only trip if it detects a leakage of current to earth somewhere on your side of it. 

It does this by essentially measuring the current flowing in both the live and neutral conductors, and if it sees a difference (of over ~80mA, in your case), it trips.

It could be a number of things causing it to trip...

It may be faulty (it's done pretty well at 40+ years) and tripping at a very low leakage current, in which case, it needs replacing.

Or it could actually be working fine, it's just that there's already a small amount of earth leakage in the circuits throughout the house, which gets a little bit worse in wet weather... just worse enough to push the RCD over it's trigger threshold.

If any part of the house wiring is anywhere near as old as the RCD, I'd say this is most likely to be the cause.  A build up of dust and dirt behind any of the socket outlets or switches, or junction boxes, etc could easily create a low resistance path to earth - that gets worse when there's a bit of moisture in the air.

If you can find a competent electrician, they should be able to test the RCD for you, to establish whether it's working as it should. Then they'd hopefully do a 'whole house' insulation resistance test, which will highlight if there is any significant earth leakage - and if there is, start to identify which particular circuit(s) are the cause of the issue. 

If you have any circuits that run outside of the house (outside lighting, spurs off to a shed, etc), that might be a good place to start.  Look for signs of water ingress, failing rubber seals, that sort of thing.  Other likely culprits include water heaters, washing machines etc.

But do get that RCD checked - at 40+ years, it's done it's bit.  It might just save your life one day. 

It will be fair to say it is a spot on assesment of what the problem likely are. Just to add 1 point concerning the Earth leakage ( RCD) the correct RCD replacement would be of 30ma models as 80ma are only allowed in certain industrial and commercial enviroments if this is a house dwelling the regulation stipilates 30ma sensitivity.

[HedgeSlammer]

Thanks, @TaliaB.   Yes, the requirement for 30mA is the same in the UK/Europe - I don't know exactly what the the regs in .za state, so I didn't say.

Another possibility occurred to me - not generally an issue in the UK, but I've come across it elsewhere:  Little creatures!  I've seen ants completely filling light switch back boxes and causing earth leakage... I think one ant wanders in to the back of the switch, gets fried and in the process releases a pheromone (We're under attack!), so more ants pile in to join the fight.  The end result being literally a solid, square cake of dead ants the same shape as the box.  Geckos are pretty good a squeezing into tight spaces, too - their urine is very corrosive to copper.  Damp spiders web / nests / eggs will conduct a little.

Then there's rats.  I recall (here he goes again) an industrial unit that had a tiny leak in the roof - just a drip when it rained hard and the wind was in just the right direction.  Where this drip landed was right on top of a twin+earth cable supplying the lighting circuit in the roof.  The rats had decided that this was a good place to get a drink, one of them deciding to have a little nibble at the PVC insulation... right on the exact spot where the drip would land, causing a L-E fault.

I used to marvel at the rat's apparent ability to chew live copper and get away with it... I've seen 25mm² tails stripped bare where they pass through a wall cavity (a nice surprise!), but there's never any 'body'.  Then I learned about their 'no man left behind' policy, specifically how they incorporate it into their idea of 'lunch'. Ewww. 

But yes, get that RCD (ELCB) swapped out for a new 30mA one.  It being your main switch does complicate thing a little - again, I don't know how it works where you are, but here I would have to pay the DNO (network operator) to do a disconnect/reconnect as the incomer fuse would have to be re-sealed.  Under no circumstance should it be attempted 'hot' (live).  Better to cut the seals and pull the main fuse (and face the consequences, if any) than risk your life.  There's always the 'it was like that when I got here' defence to fall back on.   Possibly not as convincing if you've had the property several years or they do meter readings in person (for that we have the 'some bigger boys did it and ran away' defence).

The main issue for you now is that if/when you swap the RCD for the correct one, you'll likely get a lot more tripping - so a bit of a dilemma for you.  Spending money to make the 'problem' worse.  Try to think of the 'problem' as being the fault(s) that cause the tripping.  The tripping itself is the systems solution to the problem (as in 'disconnecting the power before someone gets hurt').

There is quite a lot you can do before getting it checked/swapped out though.  With the supply switched off, it can't hurt to methodically take off the switches/sockets and check/clean the back boxes and termination of the wires behind.  Even just replacing the switches and sockets could be enough (here in the UK it's one of the few things deemed 'non-notifiable work', so a competent DIYer can legally do for themselves) - they get old, the contacts get oxidised, they wear out.  New ones are not that much, + they look so much nicer.

Along the way, look for anything that could cause an issue, when you put things back together, try to ensure that the wires behind are not in contact with or squished up against any metal back boxes, where possible.

Once you've done what you can for yourself, get an electrician in to do a quick test (or better yet, a full 'Electrical Installation Condition Report', or whatever it's known as locally) and to swap the RCD.  Hopefully you'll end up with a safe installation and still be able to afford the electricity to put into it.

[TaliaB]

@HedgeSlammer @bony999

Yeah Rcd fault finding can be loads of fun. My starting point normally i will do a ramp test on existing Rcd with all loads disconnected(breakers off) to determine how good the Rcd functionality is. Subtracting the reading from the Rcd trip value normally gives you a good indication of residual leakage current on load curcuits. I also use a milliamp clamp meter around the live and neutral of the incomer to determine the imbalance between L and N. Taking the wiring age into consideration i will also do a IR test on all the wiring and replace wiring as i go along. Also remember there is intentional leakage currents that comes from EMC filters which utilize Y capacitors almost all electronic appliances. Then you get unintentional leakage currents on faulty equipment and wire insulation breakdown especially in wet conditions. So yes fault current tracing is a meticulous task and take nothing for granted. Good db board design utilize more than 1 RCD device where curcuits are split to prevent reaching the threshold trip current of 30ma.

[Scorp007]

3 hours ago, HedgeSlammer said:

Thanks, @TaliaB.   Yes, the requirement for 30mA is the same in the UK/Europe - I don't know exactly what the the regs in .za state, so I didn't say.

Another possibility occurred to me - not generally an issue in the UK, but I've come across it elsewhere:  Little creatures!  I've seen ants completely filling light switch back boxes and causing earth leakage... I think one ant wanders in to the back of the switch, gets fried and in the process releases a pheromone (We're under attack!), so more ants pile in to join the fight.  The end result being literally a solid, square cake of dead ants the same shape as the box.  Geckos are pretty good a squeezing into tight spaces, too - their urine is very corrosive to copper.  Damp spiders web / nests / eggs will conduct a little.

Then there's rats.  I recall (here he goes again) an industrial unit that had a tiny leak in the roof - just a drip when it rained hard and the wind was in just the right direction.  Where this drip landed was right on top of a twin+earth cable supplying the lighting circuit in the roof.  The rats had decided that this was a good place to get a drink, one of them deciding to have a little nibble at the PVC insulation... right on the exact spot where the drip would land, causing a L-E fault.

I used to marvel at the rat's apparent ability to chew live copper and get away with it... I've seen 25mm² tails stripped bare where they pass through a wall cavity (a nice surprise!), but there's never any 'body'.  Then I learned about their 'no man left behind' policy, specifically how they incorporate it into their idea of 'lunch'. Ewww. 

But yes, get that RCD (ELCB) swapped out for a new 30mA one.  It being your main switch does complicate thing a little - again, I don't know how it works where you are, but here I would have to pay the DNO (network operator) to do a disconnect/reconnect as the incomer fuse would have to be re-sealed.  Under no circumstance should it be attempted 'hot' (live).  Better to cut the seals and pull the main fuse (and face the consequences, if any) than risk your life.  There's always the 'it was like that when I got here' defence to fall back on.   Possibly not as convincing if you've had the property several years or they do meter readings in person (for that we have the 'some bigger boys did it and ran away' defence).

The main issue for you now is that if/when you swap the RCD for the correct one, you'll likely get a lot more tripping - so a bit of a dilemma for you.  Spending money to make the 'problem' worse.  Try to think of the 'problem' as being the fault(s) that cause the tripping.  The tripping itself is the systems solution to the problem (as in 'disconnecting the power before someone gets hurt').

There is quite a lot you can do before getting it checked/swapped out though.  With the supply switched off, it can't hurt to methodically take off the switches/sockets and check/clean the back boxes and termination of the wires behind.  Even just replacing the switches and sockets could be enough (here in the UK it's one of the few things deemed 'non-notifiable work', so a competent DIYer can legally do for themselves) - they get old, the contacts get oxidised, they wear out.  New ones are not that much, + they look so much nicer.

Along the way, look for anything that could cause an issue, when you put things back together, try to ensure that the wires behind are not in contact with or squished up against any metal back boxes, where possible.

Once you've done what you can for yourself, get an electrician in to do a quick test (or better yet, a full 'Electrical Installation Condition Report', or whatever it's known as locally) and to swap the RCD.  Hopefully you'll end up with a safe installation and still be able to afford the electricity to put into it.

I do prefer to isolate but have worked live on many pieces of plant in various factories. 

Always interesting to read others way of working or fault finding. Decades ago running a section on a shift basis where the plant ran 24/7 and only stopped for X-Mas and new year and even this was not a given we used to change minor thing alive. You just had to know what you doing and make sure there is some form of isolation between the possible fault and where you working. 

In a DB  if you have made sure all live wires are in fact dead when the main switch/E/L is off you CAN change without the supply authority isolating. In our area houses are fed from a kiosk which is no longer locked as we need to see our meter readings to submit. Over time less meter readers so instead of getting way out estimates the on line submitting works great. Lately with the munic under strain they tend to actually read the meters monthly to get some revenue. 

Not many of these trusted units still in use. I have no trips (without reason) and the unit is still working within it's range of 20mA. I installed it as a old unit in my house 33yrs ago. 

 

[HedgeSlammer]

@TaliaB - Yes, very good point about the Y caps in all sorts of everything now.  I've had to split stuff down before... all tests fine, then the customer goes and plugs a ton of IT kit in (how inconsiderate of them!).  We always split the load between at least 2 RCDs, but now as single-module wide RCBOs are very affordable, critical circuits (freezers etc) or anything special can have their own (provided there's enough height available in the box).  It's not that uncommon to find a single RCD as a main switch, though.

@Scorp007 - That Heinemann looks to be of a fine vintage, it will likely outlive us all. 

How are things usually arranged in .za at a domestic Metering point?  Here it's almost always [Grid -> 'company head', which includes Cut out (100/80/sometimes 60A cartirdge fuse, sealed with wire and numbered crimp) -> Meter -> consumer unit] - all either within the property or in a cabinate attached to the wall of the property.  That's why they've been pushing smart meters so hard here - so they can cut you off without needing access.

Yep, true that working hot is unavoidable sometimes. I have a 'rule of 3', that is 3 things between me and not going home tonight... Usually VDE tools + thick rubber gloves + a rubber mat that I keep on hand.  But there's always things out there just waiting to get you.  Had a close one a couple of months back:  Friday night, a water heater in a tank, awkward access, also fed from an oil boiler loop.  Isolated the board from which it was fed + 2-pole isolator next to the unit.  Muppet-face here didn't spot that the boiler (inc it's thermostat feed to the tank) was fed via a different board elsewhere in the building.  After receiving 'a bit of a tickle', I think I may have invented some completely new swear words that day, mainly directed at plumbers. 

But yes, working on live equipment should be strongly discouraged, even if we occasionally do it ourselves.  'Duty of care' and all that. 

 

[Vaal]

Bonny999 please confirm where your RCD/EL is, is it before your inverter or after the inverter (between inverter and load)?

If I remember correctly it is best to use a Type B Rcd in a system with a inverter. 

Can you maybe borrow, beg or steal a meggar from somebody and test for any leakage down to earth?

Happy hunting. LoL

[bony999]

Hello vaal ,Hedgeslammer, Scorp007, TaliaB, Moffat, jbroo, Thunderdolt and Vaal. I will try to answer all of the respnses in this message, forgive me if I miss something!

I have been off the forum for a few days and I come back to find this wealth of information. I am very grateful for all of the responses. I am in the process of getting new sockets for the house as we speak. I am going to check each back box and cabling as I go and replace each and every one I have. The option of changing the main Elcb is the next thing after changing all of the sockets.

I will check the links for the power conditioning supplies suggested too.

I appreciate that changing my poor old unit may in fact make the whole system more sensitive so I will take advice form an electrician when all sockets are replaced.

The breaker I have currently is in the main distribution board of the house and it is the main switch to the property.

The inverter is in a purpose built cabinet with all of the protective devices fitted for the battery, the solar panels, the incoming standby power supply as well as the mains output from the cabinet. The output of the cabinet from the inverter then supplies a seperate consumer unit that only feeds solar powered sockets in the home. i.e. I have both main supply from the electrical company as well as a seperate set of supplies from the batteries and solar. The solar sockets are fed from the inverter output and there is no point at which the incoming mains used as a standby supply to the invetrer, is able to feed the solar sockets or vice versa. This was something I specified when I purchased the system and as such removes any issue of the inverter back feeding the grid.

I will try to borrow a meggar from a chap I know in an electrical engineers and see what leakage I have to earth. My feelings are that after all of reading the previous information I should start with the stuff I can do easily and then leave the difficult stuff to a qualified electrician.

I thank all of you for taking the time to reply and I will feed back if I make any discoveries as to the cause or even the solution to the problem.

Many thanks and have a great new year.

Regards

Bony999

I will not be removing the Elcb myself and I think I would have a job convincing the supplier that someone else removed the seal as I have been here for a couple of meter changes over the years.

 

[Scorp007]

1 hour ago, bony999 said:

Hello vaal ,Hedgeslammer, Scorp007, TaliaB, Moffat, jbroo, Thunderdolt and Vaal. I will try to answer all of the respnses in this message, forgive me if I miss something!

I have been off the forum for a few days and I come back to find this wealth of information. I am very grateful for all of the responses. I am in the process of getting new sockets for the house as we speak. I am going to check each back box and cabling as I go and replace each and every one I have. The option of changing the main Elcb is the next thing after changing all of the sockets.

I will check the links for the power conditioning supplies suggested too.

I appreciate that changing my poor old unit may in fact make the whole system more sensitive so I will take advice form an electrician when all sockets are replaced.

The breaker I have currently is in the main distribution board of the house and it is the main switch to the property.

The inverter is in a purpose built cabinet with all of the protective devices fitted for the battery, the solar panels, the incoming standby power supply as well as the mains output from the cabinet. The output of the cabinet from the inverter then supplies a seperate consumer unit that only feeds solar powered sockets in the home. i.e. I have both main supply from the electrical company as well as a seperate set of supplies from the batteries and solar. The solar sockets are fed from the inverter output and there is no point at which the incoming mains used as a standby supply to the invetrer, is able to feed the solar sockets or vice versa. This was something I specified when I purchased the system and as such removes any issue of the inverter back feeding the grid.

I will try to borrow a meggar from a chap I know in an electrical engineers and see what leakage I have to earth. My feelings are that after all of reading the previous information I should start with the stuff I can do easily and then leave the difficult stuff to a qualified electrician.

I thank all of you for taking the time to reply and I will feed back if I make any discoveries as to the cause or even the solution to the problem.

Many thanks and have a great new year.

Regards

Bony999

I will not be removing the Elcb myself and I think I would have a job convincing the supplier that someone else removed the seal as I have been here for a couple of meter changes over the years.

 

Thanks for explaining your very special system. May it all work out as planned. 

You don't mention where the voltage stabiliser will come into play. Not all sparkies get to work with stabilisers

[bony999]

Hi Scorp007

I was thinking of fitting the voltage stabiliser before the input to the inverter and its protection devices so that at least I would know if there was some issue with the inverter when in line mode, which it is overnight, to charge the batteries.

In the interim I have changed the sockets in my house that are on the DNO supplies and have also disconnected the fridge and freezer from the solar supplied sockets. This seems to have had some sucess as so far the system has not tripped out overnight at all.

I am by no means an electrician but I do understand a lot of the principles and it occured to me that maybe the fridge and or freezer coming on when the system was in line mode may have been the cause. I know the compressors pull a fair bit on start up and maybe it is the combination of the two perhaps starting at the same time that sets off the main switch when it is supplying power to the batteries in line mode.

So far the system if working overnight as it should and I have now got new sockets all around the house apart from a couple. I have yet to see how it performs when we get some more wet and windy weather, which is mainly when the issue occured. If it indeed stops tripping under any of the previous circumstances I will post back to let anyone else who has been kind enough to contribute know how it was resolved.

As ever I am grateful for the reply. Happy new year

Regards

Bony999