Voltage drop in house - what to expect

05-02-2018 7:16pm

Dardania wrote: »

Could any of those loads have any dodgy harmonics, causing the trip?

The EV charger would have an DC charging circuit which I would suspect is a nonlinear load, so yes.

Those heat pumps have VSDs?

Not likely in a small domestic heat pump.

05-02-2018 7:19pm

KCross wrote: »

While charging it takes a constant 30A, usually for about 2-3hrs depending on how low the battery was. It always charges between 5-8am so that its ready to go when I wake up.

I am guessing that you mean 30A output from the car charger, not 30A on the input at 230 V ?? Please confirm.

KCross · 05-02-2018 10:03pm

brightspark wrote: »

It could also be a loose/bad connection on your own main incoming cables/fuses/circuit breakers.

Any sign of heating anywhere?

Im not a spark but I haven't seen any of those signs in the meter or distribution board but as I said Im not a spark so I could miss it.

2011 wrote: »

The EV charger would have an DC charging circuit which I would suspect is a nonlinear load, so yes.

Its a AC charge point. The AC-DC conversion occurs in the car itself. I doubt/dont-think that would have any effect back in the house electrics but I could be wrong.

2011 wrote: »

I am guessing that you mean 30A output from the car charger, not 30A on the input at 230 V ?? Please confirm.

Not sure of the distinction you are making.
Its 30A being drawn by the car from the charge point. The car has a 6.6kVA charger in it.

An EV charge point is no more than a fancy outdoor socket with some smarts built in to handshake with the car.

05-02-2018 11:27pm

KCross wrote: »

Its a AC charge point. The AC-DC conversion occurs in the car itself. I doubt/dont-think that would have any effect back in the house electrics but I could be wrong.

I was just Googling this, you are correct the DC conversion happens in the car. However this makes not difference, the circuit is exactly the same, therefore the effects are too.

Not sure of the distinction you are making.
Its 30A being drawn by the car from the charge point. The car has a 6.6kVA charger in it.

If a heater were to draw 10 amps from a car battery the power dissipated would be 120 watts (12 x 10).
Whereas if a heater were to draw 10 amps from a 230V supply the power dissipated would be 2300 watts (230 x 10).
My point is that 30A doesn't mean much without a voltage reference.

When you said that 30 A was drawn I was not sure if meant that this was the DC current drawn from the output side of the car charger at a (possibly) lower voltage or if it was 30 A drawn from the mains voltage supply.

Out of interest how did you measure 30A ? Is this displayed on the EV charger or on the car dashboard ?

xl500 · 06-02-2018 10:38am

KCross wrote: »

While charging it takes a constant 30A, usually for about 2-3hrs depending on how low the battery was. It always charges between 5-8am so that its ready to go when I wake up.

What type of Ev do you have can you not set it to charge earlier in the night so as not to coincide with Heat Pump Starting

If EV is Charging at 30a and Heat pump starts heat Pump could be tripping on UV ie Low Voltage protection

KCross · 06-02-2018 10:48am

xl500 wrote: »

KCross wrote: »

While charging it takes a constant 30A, usually for about 2-3hrs depending on how low the battery was. It always charges between 5-8am so that its ready to go when I wake up.

What type of Ev do you have can you not set it to charge earlier in the night so as not to coincide with Heat Pump Starting

Shifting the charging wouldn't help. The heat pump comes on whenever it wants to 24/7.

xl500 wrote: »

If EV is Charging at 30a and Heat pump starts heat Pump could be tripping on UV ie Low Voltage protection

Yes, thats what we believe it is, but probably only happens when the voltage is already low to begin with, as both heat pump and car charging occur at the same time everyday and it isn't tripping daily.

KCross · 06-02-2018 10:51am

2011 wrote: »

If a heater were to draw 10 amps from a car battery the power dissipated would be 120 watts (12 x 10).
Whereas if a heater were to draw 10 amps from a 230V supply the power dissipated would be 2300 watts (230 x 10).
My point is that 30A doesn't mean much without a voltage reference.

When you said that 30 A was drawn I was not sure if meant that this was the DC current drawn from the output side of the car charger at a (possibly) lower voltage or if it was 30 A drawn from the mains voltage supply.

Out of interest how did you measure 30A ? Is this displayed on the EV charger or on the car dashboard ?

Got ya, its 30A @ 230V. The car charger is 6.6kVA.

There is an app for the car that interrogates the telematics and it shows it pulling 6.6kW. I also have an energy monitor on the charge point and can see it pulling 6.6kW and its well documented that the Leaf pulls 30A (I think its actually 29A).

xl500 · 06-02-2018 10:55am

KCross wrote: »

Shifting the charging wouldn't help. The heat pump comes on whenever it wants to 24/7.

Yes, thats what we believe it is, but probably only happens when the voltage is already low to begin with, as both heat pump and car charging occur at the same time everyday and it isn't tripping daily.

Ok its almost certainly UV and will probably get worse as other houses increase loads

I was just thinking that those times it tripped was probably the same time as heavy loads in other houses If you set the Car to charge earlier then that load would be removed at that peak time

Its not a long term solution but may help in the short term Voltage is probably much better in the Early part of the night ie 2-4am

KCross · 09-02-2018 10:12pm

Voltage monitor from ESB attached!

They had to cut power to the house to attach it!

It has a normal clamp on the live but it also has two other cables connected to the meter so they had to cut power to connect those.

I presume that's so they can monitor voltage and current?

Anyway, it's in for a week I think so let's see what happens.

09-02-2018 10:15pm

Will be interested to see what happens.

xl500 · 24-02-2018 9:38am

KCross wrote: »

Voltage monitor from ESB attached!

They had to cut power to the house to attach it!

It has a normal clamp on the live but it also has two other cables connected to the meter so they had to cut power to connect those.

I presume that's so they can monitor voltage and current?

Anyway, it's in for a week I think so let's see what happens.

any results from Voltage monitor

KCross · 24-02-2018 9:44am

They haven't come back for the monitor yet.

KCross · 16-03-2018 7:45pm

After sending them an email earlier in the week they came to pickup the monitor today.

Hopefully I'll have a result in a week or two. I dont know how long it takes them to analyse the data and come up with a solution, if there is indeed a voltage issue.

Will post once I hear something.

KCross · 03-04-2018 1:30pm

The results are in! Drum roll!....

No issue, according to ESB. Its within spec.

They do see some instances where it is outside the 10% allowed deviation. I requested the raw data and they sent me a graph, which I will post shortly. I need the raw data though as the graph is all bunched up data that doesnt show the spikes. e.g. it doesnt show any instances below 215V and I know it goes there and they have admitted it too.

I am waiting on a call from them today to discuss the results as I'm not entirely happy considering they are admitting it has on occasions gone below 207V!

Maybe there is no issue. Maybe its just their first reply to see if I will go away!

I'll be interested in your opinions once I get the graph and stats posted.

Dardania · 03-04-2018 2:09pm

KCross wrote: »

The results are in! Drum roll!....

No issue, according to ESB. Its within spec.

They do see some instances where it is outside the 10% allowed deviation. I requested the raw data and they sent me a graph, which I will post shortly. I need the raw data though as the graph is all bunched up data that doesnt show the spikes. e.g. it doesnt show any instances below 215V and I know it goes there and they have admitted it too.

I am waiting on a call from them today to discuss the results as I'm not entirely happy considering they are admitting it has on occasions gone below 207V!

Maybe there is no issue. Maybe its just their first reply to see if I will go away!

I'll be interested in your opinions once I get the graph and stats posted.

I wonder if their defence will be that something happened out on the network somewhere that affected you, and they have addressed the problem so that it won't occur again? You were the only victim of a brownout effectively, due to your high demand.
What's your next step if it happens again - CRU?

KCross · 03-04-2018 2:42pm

Just off the phone with them.
They are allowed a 5% deviation from the 10% range... i.e. they have to provide voltage at 207V-253V but they can go outside that range 5% of the time... they are well within that 5% in my case so it meets the spec.

The spec (EN50160) is fairly flexible and gives them a lot of wriggle room so I think I'm at the end of the road.

They have also now sent me the raw data which is aggregated at 10min intervals showing min/max/avg for voltage and current. I'm still digesting that data.

Example

13 Mar 2018 05:16:54
V min/avg/max 215.9. 218.8. 222.4
A min/avg/max 40.8 52.3 63.8

The car and the heat pump would be running together at this time which would be 30A+17A and then background house load. The 63A max is probably the start-up current when the heat pump comes on.

Another example..
13 Mar 2018 23:46:54
V 206.8 217.8 225.3
A 16.2 52.2 98.2

tweek84 · 03-04-2018 4:11pm

KCross wrote: »

J

Another example..
13 Mar 2018 23:46:54
V 206.8 217.8 225.3
A 16.2 52.2 98.2

98Amps or am i reading that wrong?

xl500 · 03-04-2018 4:11pm

KCross wrote: »

Just off the phone with them.
They are allowed a 5% deviation from the 10% range... i.e. they have to provide voltage at 207V-253V but they can go outside that range 5% of the time... they are well within that 5% in my case so it meets the spec.

The spec (EN50160) is fairly flexible and gives them a lot of wriggle room so I think I'm at the end of the road.

They have also now sent me the raw data which is aggregated at 10min intervals showing min/max/avg for voltage and current. I'm still digesting that data.

Example

13 Mar 2018 05:16:54
V min/avg/max 215.9. 218.8. 222.4
A min/avg/max 40.8 52.3 63.8

The car and the heat pump would be running together at this time which would be 30A+17A and then background house load. The 63A max is probably the start-up current when the heat pump comes on.

Another example..
13 Mar 2018 23:46:54
V 206.8 217.8 225.3
A 16.2 52.2 98.2

Is there any chance of Putting a Soft start control on Heat pump or you could get a car charger which will adjust its output depending on Voltage of Mains I think some of the newer smart chargers do this

KCross · 03-04-2018 4:26pm

xl500 wrote: »

Is there any chance of Putting a Soft start control on Heat pump or you could get a car charger which will adjust its output depending on Voltage of Mains I think some of the newer smart chargers do this

There is a soft starter on the heat pump already.

There are charge points that do as you say.... the Zappi will reduce power to the car when the current goes above a certain level. The Tesla Wall connector will share the load to two EV's to ensure you don't blow the fuse.

When I get a second EV I will be installing one of those but however I cut it, when I add a second EV I will be increasing the load not decreasing it so I don't know how that is going to pan out.

The guy did say that there is no issue with putting another monitor in when that happens.

KCross · 03-04-2018 4:36pm

tweek84 wrote: »

98Amps or am i reading that wrong?

Correct, thats a max rather than a sustained load.

The HP could have been starting while there was already high loads and so it could spike. It is soft start limited to 33A and runs at about 17A.

The car draws 30A continuous.... not sure if it spikes on start or not.

Any other devices that happen to be running (oven, kettle etc) could have been on that that time... I don't know.

That particular data point seems an outlier example tbf. Most of the data points are <60A max when the car and HP are running together.... not sure why that 98A happened.

I did see one other weird example...
17 Feb 2018 14:06:54
V 212.4 223.5 228.1 (min/avg/max)
A 3.7 18.7 110.6

No idea how/why 110A would be possible since 212V is not the lowest voltage recorded (205V) and the average was only 18.7A! Measurement anomalies, I suppose.

FranklinMint · 03-04-2018 4:58pm

That's quite a bit on the 16kva supply

Can you stagger the use of the appliances so they don't overlap with the pump and charger?

Any rural 16kva installation i worked on was always a high quality supply,you wouldn't be expecting major voltage drop coming in .

Dardania · 03-04-2018 4:58pm

Of all the numbers you’ve shown for voltage, none of them appear to be above 230V?
I must have a read of that EN standard - it’s one thing to allow deviations from the norm, but surely they need to at some stage be around 230V to comply with the EU harmonised voltage?

KCross · 03-04-2018 5:14pm

FranklinMint wrote: »

That's quite a bit on the 16kva supply

Can you stagger the use of the appliances so they don't overlap with the pump and charger?

Any rural 16kva installation i worked on was always a high quality supply,you wouldn't be expecting major voltage drop coming in .

The two offending items are the car charger and the heat pump. I can move the car charger around but I cant really change the heat pump. It comes on/off as it sees fit so moving the car wouldn't help as they would still clash at some point.

I run some other appliances at night (dishwasher/dryer etc) but they all come on at the very start of night saver rate so they are not the issue and don't ever clash with the car which usually starts between 3-5am and goes off at 8am.

Dardania wrote: »

Of all the numbers you’ve shown for voltage, none of them appear to be above 230V?
I must have a read of that EN standard - it’s one thing to allow deviations from the norm, but surely they need to at some stage be around 230V to comply with the EU harmonised voltage?

Still analysing the data in excel right now, they aggregate the data over 10min intervals and then give the min/avg/max of each of those 10min intervals.... if I look at that avg value and get an average of that over the entire 30+ days it gives me 224V.

The max voltage value is rarely at 230V.... usually 224-228V.. again, within spec as far as they are concerned.

FranklinMint · 03-04-2018 5:36pm

The average supply voltage 218v at 50amp load is a bit lower than you would like to to see for a 16kva supply.

You say the main mcb is only 63amp

You might only have 16sq tails from the meter to distribution board ,not a factor if distance is short.

KCross · 03-04-2018 6:10pm

FranklinMint wrote: »

The average supply voltage 218v at 50amp load is a bit lower than you would like to to see for a 16kva supply.

You say the main mcb is only 63amp

You might only have 16sq tails from the meter to distribution board ,not a factor if distance is short.

I checked the tails... they are 25sq.

Just as another reference during low load....

15 Mar 2018 11:06:54
V 221.9 226.1 231.0 (min/avg/max)
A 3.5 3.8 4.5

KCross · 12-04-2018 5:34pm

For posterity here is the 2 page report they gave me...
448010.pdf

Here is the regulation they work towards...
448011.pdf

Note the 2nd row in that table. 230V±10% for 95% of the time.
Thats the one they quoted me to show that they are compliant.

For the ~5000 10-min measurement intervals(35 days) I had, 15 intervals were outside the 230V±10%. It would have to happen about 250 times for them to agree that there was a problem that required action on their part!

15 times in 35 days is often enough to cause me an issue if high usage happens to coincide with the heat pump coming on.... which has happened twice in 2 months.

While ESB Network consider the voltage fine it doesnt mean you dont have a low voltage problem!

The heat pump manufacturer has shown me how to up the trip limit on the heat pump a couple of amps as it is set lower than spec by default. So, at least I have that option if it becomes a regular occurrence.

On the the graph, it is a little misleading as it looks like the voltage is between 220-230 all the time. It's not.

They sent me the raw data in Excel format as well.

They have voltage and current readings averaged over 10min intervals and they give min/average/max values for voltage and current for each interval.

The min voltage I got over the 35 days was 205V!
I had 235 intervals that had a min <215V

The spikes in current each day is when the car is charging and the heat pump is on, which would equate to 30A+17A+background-load=50-60A.

vintagevrs · 26-04-2020 12:19pm

Mods,

Sorry to revive an old thread but seems to be very similar situation to me in regards to problem with a heat pump. I can start a new thread if needed?

We have an upgraded supply as heat pump was in spec when building house and ordering ESB connection, so we have a 16kva connection.

Our heat pump over the last few years has destroyed a number of soft start units. This time last year, ESB put a meter on the line, and admitted the line was out of spec. They then said they would do some upgrade work, then reneged on this as a level 2 manager got involved. They replaced the cable from the pole to my box, and I was suspicious they were only doing this as it was the most visible work we would see, as it was at our home but would do no harm. I asked why they were replacing it, had they suspected it to be faulty and they hadn't. I had a complaint open with the regulator about ESB lack of action, and that is now closed with a tiny payment to me from ESB recommended by the regulator for their delay in action.

So the heat pump can then work for months without issue and then start giving issue again. Before Christmas it started playing up again. The issue is that the compressor does not start, but the heatpump (Nibe) does not realise this so no errors/alarms and only sign is that the hot water is no longer hot. To fix this, power cycling the pump sorts it. Issue may not return then for a couple of days.

Problem has been getting worse lately though, maybe every 2nd or 3rd day. I recently got a Omega voltage logger and have this installed beside the heat pump to see if it is the supply to the pump, might be internal wiring issue.

This morning the pump failed to start and I have the voltage monitor on at the time, capturing readings every 5 seconds.

This stuff isn't my area at all so I am not sure if the variation here is totally normal. I know ESB won't really look at any issue below 207V?

Does the fact the heat pump had issue during this time, point to an issue more so with the pump rather than the supply?

Sorry for long post

Cheers

Hintel · 26-04-2020 12:24pm

Those voltage variations look normal at first glance

Hintel · 26-04-2020 12:48pm

Fluctuations^^

Tails142 · 26-04-2020 12:49pm

I'd agree that those volt levels are in the normal range from what I can see

Voltage drop in house - what to expect

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