High Mains Voltage

[pearley]

We have a Victron Isolation Transformer and the mains voltage on the boat sits at 255 with no load but drops to 239 volts when a 2kw load applied. According to Victron Community Forum this is normal.

 

But, when the washing machine heater switched off the load to move the drum us fairly minimal so voltage rises again to 255. Is this likely to do any harm?

[nottheone]

It is a little on the high side it really shouldn't be over 253. What are you using to measure the voltage ?

[BEngo]

NO. Acceptable mains voltage in UK is 230 V -6% +10%. An extra 2V is not going to cause a problem, even if your multi meter is accurate, and calibrated.

N

[Tracy D'arth]

15 minutes ago, pearley said:

We have a Victron Isolation Transformer and the mains voltage on the boat sits at 255 with no load but drops to 239 volts when a 2kw load applied. According to Victron Community Forum this is normal.

 

But, when the washing machine heater switched off the load to move the drum us fairly minimal so voltage rises again to 255. Is this likely to do any harm?

255 is outside the allowable tolerance for UK mains.

"IET Forums - UK Supply Voltage Spec.

https://www2.theiet.org › forums › forum › messageview.cfm?catid=205&threadid=21536

Aparently the EU harmonisation process expected this year will permit supply voltage range in UK to broaden to between 207v and 253v (+/-10%)! I thought that the change had already been made at the beggining of this year and that the lower limit was now 207 volts, the high limit remaining at 253 volts."

 

Is there no adjustment to tappings on your transformer?

 

The life of some electrical items will be shortened at higher voltages but how small a load does it take to drop the voltage down?

The volt drop will not all be due to load on the transformer but the volt drop on all the cabling from the substation to your boat, especially if you are sharing a power supply with others or you have long shore cables.

[David Mack]

UK mains electricity is supposed to be 230V -6% / +10% i.e. between 216.2V and 253V. And mains appliances should be tolerant to a wider range than that. So you should be fine.

 

See for example https://www.spenergynetworks.co.uk/pages/voltage_changes.aspx

Edited October 10, 2021 by David Mack

[GUMPY]

I had  similar with my Airlink.

Most transformers have a resting o/p voltage 10v above the nominal voltage to allow them to produce nominal voltage at full load.

If the input voltage is high then the output voltage will be higher.

With mine on my previous mooring the resting o/p voltage was 257v. I made an educated decision to reverse the transformer input/output this didn't give me as good regulation but voltages were 247v supply,  235v resting output, 220v loaded output. Worked like this for 12 years.

I have now put it back to normal as my new mooring is 230v supply at best. 

 

Edited October 10, 2021 by Loddon

[BEngo]

The voltage regulation of the IT is pretty poor. Your example is about 6%, at, I guess, less than full load into a resistive load.  I would expect about 3%.

 

N

[GUMPY]

Unfortunately your voltages are all within UK  spec as the input voltage will be in the region of 245v well within tolerance.

[GUMPY]

10 minutes ago, BEngo said:

The voltage regulation of the IT is pretty poor. Your example is about 6%, at, I guess, less than full load into a resistive load.  I would expect about 3%.

 

N

No it was pretty much at full 16amp load for the test  I used 3x 1000w par cans and a 500w par can😱 

I often saw 20+amps being drawn through a 16amp breaker when I had the barge. With a 3kw Immersion, Washer and separate dryer but not all three on at the same time 

Edited October 10, 2021 by Loddon

[BEngo]

16 minutes ago, Loddon said:

No it was pretty much at full 16amp load for the test  I used 3x 1000w par cans and a 500w par can😱 

I often saw 20+amps being drawn through a 16amp breaker when I had the barge. Immersion, Washer and separate dryer

Not your Airlink,   writing about the OP's Victron.

 

N

[GUMPY]

5 minutes ago, BEngo said:

Not your Airlink,   writing about the OP's Victron.

 

N

Sorry assumed it was mine as post was just after my post😎

[PeterF]

I have read a Victron document that states the IT output voltage is 5% above the input when unloaded. According to the measurement from the Multiplus on the Cerbo GX it is 263V, which means the incoming mains in the marina is 250V. I used a cheap DVM and confirmed that the incoming mains was well above 230V but within acceptable range.

[pearley]

Not longer after the original post the halogen lamp inside the electric oven 'blew'. I didn't think about it at the time and just replaced it. 

 

After a long gap that one blew last weekend. The next one until this morning and that one this evening.

 

If it was a car blowing halogen headlamp bulbs I would immediately suspect alternator overcharging. So, could this high mains voltage be responsible for the oven light blowing 

 

The replacement lamps have come from different sources. One from Neff only a few days, the longest lasting one from the local appliance shop.

 

The lamp is G9, 25w Halogen specified for 300C

 

[TheBiscuits]

7 hours ago, pearley said:

The lamp is G9, 25w Halogen specified for 300C

 

Are you touching the lamp with your fingers when installing it?  Use gloves or a clean cloth so you don't leave oil residue from your fingerprints on the glass.

 

 

Edited March 5, 2022 by TheBiscuits
oops! wrong one...

[blackrose]

I would have thought a light bulb for an oven would be designed to resist a bit of oily residue? 

[Ronaldo47]

The lives of traditional tungsten and halogen lamps will be drastically reduced by over-voltage. My cousin's house is just over the road from their substation, and their mains voltage is close to the upper legal limit  Their bulbs never lasted long until they had dimmers fitted.

[pearley]

8 hours ago, TheBiscuits said:

 

Are you touching the lamp with your fingers when installing it?  Use gloves or a clean cloth so you don't leave oil residue from your fingerprints on the glass.

 

 

No 

I do.

[pearley]

So what I'm asking is that UK mains voltage should be 230 -6 % or +10%. So maximum is 253 volts. We are seeing up to 256, actually 253 at moment. I can't see that the tolerance in the lamp is so tight that the extra 3 volts would make much difference to the lamp life.

 

Perhaps it's just an indication of how crap modern, probably Chinese made, lamps are.

[ditchcrawler]

52 minutes ago, pearley said:

So what I'm asking is that UK mains voltage should be 230 -6 % or +10%. So maximum is 253 volts. We are seeing up to 256, actually 253 at moment. I can't see that the tolerance in the lamp is so tight that the extra 3 volts would make much difference to the lamp life.

 

Perhaps it's just an indication of how crap modern, probably Chinese made, lamps are.

My ex misses and husband had the same problem. I advised him to monitor the voltage which he did with some sort of software and then presented the results to the energy supply company. If you dont monitor it 24/7 you don't know what its going up to.

[GUMPY]

1 hour ago, pearley said:

So what I'm asking is that UK mains voltage should be 230 -6 % or +10%. So maximum is 253 volts. We are seeing up to 256, actually 253 at moment. I can't see that the tolerance in the lamp is so tight that the extra 3 volts would make much difference to the lamp life.

 

Perhaps it's just an indication of how crap modern, probably Chinese made, lamps are.

Is that 256 at the supply or the boat side of an isolation transformer?

[pearley]

2 hours ago, Loddon said:

Is that 256 at the supply or the boat side of an isolation transformer?

That's on the boat.

[GUMPY]

So if you have a transformer it's going to be less at the supply and it will be within spec.

As I mentioned earlier you could, at your own risk, rewire the transformer so the input is the output as I did on mine.

This will reduce the voltage on the boat to about 230v. The regulation of the transformer will not be as good but so long as you are not running it at maximum load it won't matter.