need someone good with electronics for this one

mukki

got a huge esb bill it was 10 times what i was expecting, ended up at €851 for 2 months, about 70Kwh between 8and 10 every day (day rate)


anyway i moved house, esb checked the meter (new digital one), and its working fine

getting bills, solicitors letters and debt collectors letters, but i just isist that i used no more electricity then usual


just remembered tonight that i had bought a wi-fi router in december, and set it up at the back of the telly (about 10feet from my digital esb meter), but moved it into the corridor about 6 weeks later


anyone think that the wifi could interfere with the meteres circut boards

Michael Collins

Hey. I'd say that the Wi-Fi router interfering with it is very unlikely. Now are you saying that according to the ESB you used 70 kWh of energy between 8.00 am - 10.00 am everyday? If so how did you get this breakdown? Normally you just get the total kWh used for the period.

Anyway just taking this 70 kWh everyday for two months makes 3,920 units and @ 12.73c per unit gives a total of ~€500 plus VAT at 13.5% gives ~€568. So this obviously is making your bill quite big, but there's still nearly €300 extra to be added on? Any idea where this is coming from?

mukki

thanks for the reply, it was around 3900 units used at the day rate, on the second last bill, when i rang in the customer reading (I moved house 3 weeks later) it was €851

they tested the meter since and and its working fine, so thats why i think something must have interefered with it for a few weeks


how would a digital power meter work,
i'd guess that is it just a digital amp meter (in parallel with a shunt resistor) and a digital volt meter (in series) and a bit of maths. so something must have caused one of the meter to get the wrong result occasionaly.

themole

There are two possiblities:
Faulty meter, so you didn't use that much electricity, or you did use it unknowlingly.

Faulty meter:
You said they checked the meter, so they prob won't check it again. The ESB have their own meter for each row of houses or substation. The total from all the houses should match their total for the area. Get on to them about this.

The only things which could have drawn that much power afaik are: cooker, electric shower, immersion heater, electric heater.

Can prob rule out the cooker.
Do you have electric heating? ie some kind of storage heater or electric bar heater?

Also did you leave your immersion heater on all the time?

If all these sources check out and the meter isn't faulty. Then maybe the neighbours are stealing your power? It happens.

Gurgle

themole wrote:

The only things which could have drawn that much power afaik are: cooker, electric shower, immersion heater, electric heater.

Not even close.
Thats 35kW of power continuously for 2 hours.
Even if all of those things were on, you wouldn't use more than 10kW.

mukki

if i had used the 8.5kW electric shower for 8hours a day, i use that sort of power, but one slight problem.... i didnt have an 8.5kW electric shower, or any electric shower


anyone know if the live got shorted to the ground ( between the meter and the fusebox) what size of current would flow, (i.e no fuses or elcb's (Earth - Live Circut Breaker)

Red Alert

Basically it would approach a zero-resistance circuit. It would either go on fire and/or a fuse somewhere would blow.

mukki

but as opposed shorting the live to the nutral would a ground rod offer 0 ohms resistance to the mains???, maybe it only let about 10kW through

themole

Gurgle wrote:

Not even close.
Thats 35kW of power continuously for 2 hours.
Even if all of those things were on, you wouldn't use more than 10kW.

What i meant was those devices are the largest draws of current in a house. They are responsbile for the most electricity being used. I didn't mean to say that they were likely to cause the amount of use he stated. Sorry if that wasn't clear

themole

Quick question.

The main fuse in a house is 64A. Voltage is 230V.

Does that not mean that the maximun possbily wattage is 64*230=14720.
So,

Thats 35kW of power continuously for 2 hours.

would not even be possbile? Or am I missing something?

Gurgle

themole wrote:

The main fuse in a house is 64A. Voltage is 230V.
Does that not mean that the maximun possbily wattage is 64*230=14720.

Its a bit more complicated with AC, can't remember the formula off the top of my head but yes you're in the ballpark.

themole wrote:

would not even be possbile? Or am I missing something?

Not be possible, not missing something.

Michael Collins

themole wrote:

So [that] would not even be possbile? Or am I missing something?

Good point. Like I said in the first post I don't know how you can get a breakdown of the bill per hour like that...

What Gurgle is refering to, I think, is the reactive power associated with an AC supply. This would make the current drawn during every half cycle a little higher, but since it gives it back every other half cycle you don't pay for it. So what this means is that while 14,720 W is theoretically the max you could draw at any instant, in actuality because of reactive power it'll be small bit lower.

Capt'n Midnight

rough calcs
€851/12.73c per unit
€851 / €0.1273 per unit = 6685 units = 111 units per day x 60 days
111 units a day = 4.625 Units an hour = 4.625 Kw average

70 units between 8 and 10 = 70 units/14 hours = 5Kw

4-5Kw is high but 5000w/230v = 21 Amperes - so won't trip the main fuse

have a look at the meter to see what is clocking up on it, turn off things or reset the switches to see what doing it, don't forget things like immersions are on thermostats so won't use power when hot.

ircoha

At the risk of getting the electric chair, perhaps as the OP moved he got an actual reading as opposed to prior estimates.

mukki

every second bill was an estimate sine i moved in

Red Alert

If someone had the kit you could get a power-meter connected to your incoming mains. It would connect across the live and neutral and have a current transformer which can be strapped onto one of the conductors. Connected up to a laptop PC for about a week it should point to where your problem is.

ircoha

mukki wrote:

every second bill was an estimate sine i moved in

OKAY. just a thought

Gurgle

Capt'n Midnight wrote:

70 units between 8 and 10 = 70 units/14 hours = 5Kw

4-5Kw is high but 5000w/230v = 21 Amperes - so won't trip the main fuse

I thought it was between 8am and 10am - i.e. 2 hours.

mukki

Red Alert wrote:

If someone had the kit you could get a power-meter connected to your incoming mains. It would connect across the live and neutral and have a current transformer which can be strapped onto one of the conductors. Connected up to a laptop PC for about a week it should point to where your problem is.

remember - i have moved house since

and the meter was working fine when i watched it for a few days, it just went mad for approx 6 weeks

i am trying to find a way to prove i couldn't have used that sot of power without noticing something, surely anythong using that sort of power would have just gotten very hot, either warming the inside of the house to such an extent that i would have to open the windows, or just going on fire

i want to be able to ring esb, ask for a manager, and just discuss the bill as if it couldn't possibley be accurate

remember this could happen to you tomorrow, i always turn off lights, tv, only half fill the kettle and i even set pc to suspends after a few minutes, i am not going to pay this, and don't wat to get a bad credit rating

A Primal Nut

Gurgle wrote:

I thought it was between 8am and 10am - i.e. 2 hours.

Well he was talking about day rate so quite clearly its 14 hours. He never mentioned am or pm if you read the original message. He didn't really need to in fairness it was obvious he meant 8am to 10 pm.

themole

A Primal Nut wrote:

Incidentally someone was trying to find the maximum wattage by mulitplying Current by Voltage. It's actually the voltage squared by current.

???????

A Primal Nut wrote:

So its actually more like 3.38 MegaWatts. But like someone said its more complicated in AC.

That does not sound right.

The entire output of all the ESB power stations is 4463 MegaWatts.

What I gave earlier was a rought calculation, more precise ones here: http://hyperphysics.phy-astr.gsu.edu/hbase/electric/powerac.html

Palladin

current by voltage will give the power output (watts) in a purely resistive circuit but there are alot of other factors which have to be taken into account . But i cant see how the meter would go crazy those things are tamper proof nowadays.

Capt'n Midnight

Years ago in the paper I saw an article about a guy who had a black box to slow the meter down (magnetic induction ?) and was up in court for it.

Anyway yer man hooked it up the wrong way around :rolleyes:

Lucky they didn't make him pay what the meter said.

toiletduck

:d

mathias

current by voltage will give the power output (watts) in a purely resistive circuit but there are alot of other factors which have to be taken into account . But i cant see how the meter would go crazy those things are tamper proof nowadays.

For what this thread is trying to do , i.e. determine how much electricity is drawn from a domestic fusebox , where all the circuit elements are as close to straight copper wire as it gets , then the resistive calculations are fine , the reactive elements of the AC mains are so small as to be completely negligible in this case.

Inductive Reactance or XL = 2pi FL ( or 6.28 x freq x inductance )
Capacitive Reactance or Xc = 1/2pi FC ( or 1/ 6.28 x freq x Capacitance )

These would combine with the resistance of the wire to determine total losses in the system , and work out true power consumption however , ...

In both cases the frequency is 50 hz , the 2 pi term is fixed , and capactance and inductance values in mains guage copper wire are so small as to be completely negligible for our purposes here ,

So straight resistive formula will do fine ,

Power = VI

or Power = I^2 R ( this is where a previous poster went wrong , mixing up his formulas ),

In the case of the mains supply a simple VI calculation based on the Voltage supply times the rating of the fuse or breaker will give the maximum possible usage in Watts as near as makes no difference.

Looking at the figures , the draw indicated on the bill is possible , so assuming that the meter is working fine then someone was stealing your electricity , a lot more common than people think these days !!

aidan24326

mathias wrote:

Looking at the figures , the draw indicated on the bill is possible , so assuming that the meter is working fine then someone was stealing your electricity , a lot more common than people think these days !!

How would they do that?