Minimum incoming house voltage

El_robbo1980

Hi all,

Would anyone know what the minimum legal incoming voltage to a domestic dwelling should be? I’m in Co. Dublin and measured a voltage at a light earlier of 218-220v. I need to re-check it at the mains board with a calibrated Fluke Meter but I’m just wondering is that low a voltage normal/allowed?

Many thanks

sparcocars

El_robbo1980 wrote: »

Hi all,

Would anyone know what the minimum legal incoming voltage to a domestic dwelling should be? I’m in Co. Dublin and measured a voltage at a light earlier of 218-220v. I need to re-check it at the mains board with a calibrated Fluke Meter but I’m just wondering is that low a voltage normal/allowed?

Many thanks

ESB networks will guarantee to provide voltage of 230v +/- 10% which equates to 207v - 253v

El_robbo1980

sparcocars wrote: »

ESB networks will guarantee to provide voltage of 230v +/- 10% which equates to 207v - 253v

Thanks a mill for the reply. Are there any possible problems with having a voltage 10V below the normal would you know?

Bruthal

El_robbo1980 wrote: »

Thanks a mill for the reply. Are there any possible problems with having a voltage 10V below the normal would you know?

Not really no. 220v is fine as long as switching on something like a shower doesn't pull it down too much.

El_robbo1980

Bruthal wrote: »

Not really no. 220v is fine as long as switching on something like a shower doesn't pull it down too much.

Thanks! Measured it there now when I suppose it’s quiet in the area and people are at work/school and it’s measuring bang on 230V. I suppose a voltage fluctuation at a busy time on a Sunday night would be to be expected?

TheBully

Yea best check at the mains as you may have some volt drop across the cables, but as stated above , 220v is fine and once it is within the tolerance of +-10% ESBN won’t entertain you. Either way 220v is fine but as I said check at your mains

John.G

Someone with a electric shower will quickly notice a voltage drop due to a cooler shower , a voltage drop to 218v will result in a 9 kw shower "loosing" almost 1 kw and if unlucky enough to have the voltage fall to 207V will loose almost 2 kw.

Bruthal

John.G wrote: »

Someone with a electric shower will quickly notice a voltage drop due to a cooler shower , a voltage drop to 218v will result in a 9 kw shower "loosing" almost 1 kw and if unlucky enough to have the voltage fall to 207V will loose almost 2 kw.

That depends on a few factors.

Showers get cooler later in the year, people adjust flow rate accordingly. I doubt they would get in with 8 or 900w loss and think something not right here. Slight reduction in flow rate and its up to temp again, or from most users point of view, turn up the temperature dial. Often showers are operating at a little below their kw rating anyway, as the voltage is a couple of volts down due to the load.

Even less noticeable in the summer.

207v might start to be noticable by the intuitive persons. But many out there are oblivious to everything.

John.G

How I intuitively noticed mine was when it returned to the normal 230/233V. For years I had had a 243/245V supply and one day last summer while actually in the shower I felt the water getting cooler and found that the above was the reason, strangely enough IW not so kindly reduced the water pressure to 1.9 bar shortly afterwards so if I had only waited I wouldn't have had to adjust my flow rate!.

coylemj

John.G wrote: »

How I intuitively noticed mine was when it returned to the normal 230/233V. For years I had had a 243/245V supply and one day last summer while actually in the shower I felt the water getting cooler and found that the above was the reason, strangely enough IW not so kindly reduced the water pressure to 1.9 bar shortly afterwards so if I had only waited I wouldn't have had to adjust my flow rate!.

The shower should be fed from the tank in the attic, the pressure should not be affected by the IW pressure.

If your shower is fed direct from from the main, the pressure would drop significantly if some of your nearby neighbours decided to fill their kettles at the same time.

KK4SAM

coylemj wrote: »

The shower should be fed from the tank in the attic, the pressure should not be affected by the IW pressure.

If your shower is fed direct from from the main, the pressure would drop significantly if some of your nearby neighbors decided to fill their kettles at the same time.

Like Electricity supply Water Mains are designed & sized to give adequate supply and not be affected by your neighbors consumption.
Mains fed showers are common !

Bruthal

KK4SAM wrote: »

Like Electricity supply Water Mains are designed & sized to give adequate supply and not be affected by your neighbors consumption.
Mains fed showers are common !

Adequate supply? Mains fed showers are often a nuisance. It is correct when a poster says tank fed is isolated from mains water pressure changes

KK4SAM

Bruthal wrote: »

Adequate supply? Mains fed showers are often a nuisance. It is correct when a poster says tank fed is isolated from mains water pressure changes

But this is incorrect you must agree ?
"If your shower is fed direct from from the main, the pressure would drop significantly if some of your nearby neighbours decided to fill their kettles at the same time.!

John.G

My 13/14 year old mains fed shower has given very steady flow even when other users opening tap(s) etc but I had I think (must look it up again) around 2.6 bar static pressure which IW has reduced to 1.9 bar static at their stopcock, the shower is still performing fine but opening a tap will definitely have a slight affect now. I agree of course that a tank fed is unaffected by mains pressure so in view of the reduction in pressure I will consider replacing my Mira Sport with a tank fed if I am still alive when this shower expires as it has been absolutely trouble free.

Bruthal

Some places even with good static pressure, were not great once a kitchen tap was opened, or even a toilet flushed. Static is one thing. But you could have good static pressure on a straw sized pipe but no use once water is flowing.

John.G

Very true indeed, I actually fitted a pressure gauge one time on my shower (just below the inlet) and I had ~ 2.0 bar static and 1.4 bar dynamic and even on opening a tap to reduce the dynamic pressure to 1.0 bar the shower flow rate was still almost perfect. I put this down to the fact that the shower has a pressure stabilizing valve BUT the (my) shower will not compensate if the dynamic pressure is 1.0 bar and then one opens a tap and that's why IMO that I can now feel the effect of someone opening a tap.

But I would add that if you have say 2.5 bar static at the IW stop cock then if you experience mains showering problems that it is due to your own pipework/usage as upstream of this static 2.5 bar is actually dynamic as its supplying all your neighbours and still reading 2.5 bar.

Bruthal

KK4SAM wrote: »

But this is incorrect you must agree ?
"If your shower is fed direct from from the main, the pressure would drop significantly if some of your nearby neighbours decided to fill their kettles at the same time.!

I never mentioned anything about the neighbour filling a kettle. Just that a mains shower is reliant on reliable dynamic pressure levels.

Bruthal

John.G wrote: »

Very true indeed, I actually fitted a pressure gauge one time on my shower (just below the inlet) and I had ~ 2.0 bar static and 1.4 bar dynamic and even on opening a tap to reduce the dynamic pressure to 1.0 bar the shower flow rate was still almost perfect. I put this down to the fact that the shower has a pressure stabilizing valve BUT the (my) shower will not compensate if the dynamic pressure is 1.0 bar and then one opens a tap and that's why IMO that I can now feel the effect of someone opening a tap.

But I would add that if you have say 2.5 bar static at the IW stop cock then if you experience mains showering problems that it is due to your own pipework/usage as upstream of this static 2.5 bar is actually dynamic as its supplying all your neighbours and still reading 2.5 bar.

Just as a matter of interest, pumped showers sort of maintain their temperature as voltage varies. The flow rate will reduce slightly with a voltage reduction.

John.G

Pumped showers are definitely more predictable here due to such variations in the mains pressure in various parts of the country, in the UK where mains pressure seems to be 4 or 5 bar, pumped showers are very rare.

adrian92

Just back to the original OP regarding voltage.

If you are in a rural location, for example, the network may not be that strong and a neighbour may have some electrical load which (inadvertently) reduce your voltage.

Tuco88

I thought most pumped showers are taken from the main water storage tank. Its more dependant on a the size of the tank and head of water pressure, than mains pressure is it not?