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I only have a somewhat vague understanding how the electrical grid works. I know the basics of energy production, and that the electricity comes to our homes using power lines resting upon those big supports we see everywhere. I would imagine the grid somehow splits into smaller sections like a tree whose endpoints are the final destinations, such as single apartments.

Let's say I fail to pay my electric bill and the power company decides to cut the electricity to my apartment. At what point of the grid is the electricity cut? The company knows my name and my address; so is there some kind of switch in my apartment building with my apartment number in it that the company comes to open? This is unlikely, since how would the company know somebody doesn't go and flip the switch again? Do they somehow control the flow of electricity from the power station? This is again seems unlikely.

Then adding to my confusion is the fact that there are of course multiple power companies, but there seems to be only one electrical grid. How does the company for which I'm paying the bill know that electricity produced specifically by them reaches MY apartment?

S. Rotos
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    in general the only part that is specific to one house or apartment is the individual meter for that house/apartment. that meter determines your usage however the power gets there, likewise that is the point at which they disconnect in the old days remove the whole meter, today can do it remotely to some extent (might have to sit out front with a wireless communications device) – old_timer Aug 23 '18 at 15:21
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    each power pole along a line can possibly be individually owned, when having fiber or cable or otherwise wanting to use those poles to run something you may have to have an individual contract per pole. Basically assume that all the material/tangible items are owned by anywhere from one to many companies. the power itself is managed by metering near sources and sinks. – old_timer Aug 23 '18 at 15:23
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    While you may be able to bypass whatever the power company does to cut yourself off, the threat of prosecution is what stops most people from doing so. After all, if you don't want to worry about having your power cut off for non-payment, you can already bypass your meter and get free electricity and never have to worry about paying your bill.... until you're caught. – Johnny Aug 23 '18 at 19:13
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    In most of the US the default mechanism for shutting off your power would be to physically remove the meter. The meter is built on a giant plug that plugs into the meter base, and if the meter is unplugged there is no "path" for electricity to enter the residence. (A clear cover is installed over the open meter base to prevent accidental contact with the wires.) – Hot Licks Aug 25 '18 at 00:56

8 Answers8

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I only have a somewhat vague understanding how the electrical grid works. I know the basics of energy production, and that the electricity comes to our homes using power lines resting upon those big supports we see everywhere. I would imagine the grid somehow splits into smaller sections like a tree whose endpoints are the final destinations, such as single apartments.

This is more or less correct. In fact, you can extend your tree analogy down to the branch circuits off of your electrical panel and the devices you have plugged into them.

Let's say I fail to pay my electric bill and the power company decides to cut the electricity to my apartment. At what point of the grid is the electricity cut?

At the most practicable location. This can be an electronic remote switch in modern systems, and is often simply disconnected by a power linesman, either at the nearest utility box, or by physically pulling out your meter head.

The company knows my name and my address; so is there some kind of switch in my apartment building with my apartment number in it that the company comes to open? This is unlikely, since how would the company know somebody doesn't go and flip the switch again? Do they somehow control the flow of electricity from the power station? This is again seems unlikely.

Controlling the flow of electricity from the power station is actually what is accomplished by disconnecting the power by a switch or other means. The most important thing to note about the means of disconnection is that it is accessible by the power company, but not by the end user or building maintenance, etc.

Then adding to my confusion is the fact that there are of course multiple power companies, but there seems to be only one electrical grid.

In many areas in order to theoretically increase market competition governments force the company that owns and maintains the grid to allow others to subcontract the sale of electricity.

How does the company for which I'm paying the bill know that electricity produced specifically by them reaches MY apartment?

The power companies don't need to track individual electrons because power use by each customer is measured, and the total output of each generator on the system is known. From this data, power companies can figure out transmission losses.

The companies that don't own the system but sell electricity are acting as a middleman and the only thing of real significance to note as a result is usually that it may actually be cheaper for you to utilize a middleman, which is somewhat counterintuitive.

Pimgd
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K H
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  • Interesting! You mention : "..is that it is accessible by the power company, but not by the end user or building maintenance, etc.". How is this accomplished? I live in an apartment building. How can the power company have access to some wiring inside the building without the building maintenance having access to it? It would be easier to understand if I lived in my own house since they could just cut the electricity into my house altogether, but in an apartment building there are several apartments and obviously they can't cut the power for the whole building. – S. Rotos Aug 23 '18 at 08:54
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    Depends on your jurisdiction; in the UK, the power company can apply for a warrant to force entry to your apartment to cut you off at the meter. – pjc50 Aug 23 '18 at 08:59
  • An area with these parameters would normally call this a utility vault, and a large apartment or commercial building will often have both a utility vault where linesmen work as well as a main electrical room, where electricians will work. Generally speaking building maintenance would likely have a master key to the room, but this is typically a heavily guarded key. Anyone with some power tools and hand tools could physically reach and open up the equipment involved, but not without breaking some laws, damaging some property, and risking their life. – K H Aug 23 '18 at 08:59
  • In the case of a meter head disconnection, if you were up for some really dangerous work, you could bypass the disconnection, but on a modern system the load would be noticed and you would just get in trouble for illegal connection. There is basically no reason someone other than a power linesman has business in a power linesman's equipment. Customers and their subcontractors have access from the main disconnecting means down. – K H Aug 23 '18 at 09:04
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    We need some more updogs. – Harry Svensson Aug 23 '18 at 09:09
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    @HarrySvensson In the UK they're called socketherds and I understand it's a more respected position. Intense job though. If a main switch goes down it can cut off power to entire cities and they have to bucket the amps by hand. – K H Aug 23 '18 at 09:14
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    Are you not referring to the joke ”what is updog? - not much. I’m okay.” – Harry Svensson Aug 23 '18 at 09:17
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    For electricians it gets used as a general purpose joke on apprentices who are feeling overwhelmed by all of the terminology, so it's just part of a larger category of jokes, including asking for wire stretchers or amp buckets, so I just went that way with it. – K H Aug 23 '18 at 09:23
  • Some types of pipe strap make very convincing updogs. Sometimes with a lot of people in on it, instead of waiting for the apprentice to ask what it is, you just let it become their default terminology and the joke is ultimately enjoyed by the people at the next site who get to have a chuckle when he gets corrected. – K H Aug 23 '18 at 09:26
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    Some new smart meters which can remotely read your energy consumption via radio or power line communication back to the power company have built in breaker for the very purpose you describe. – winny Aug 23 '18 at 10:54
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    @KH Updogs, left-handed pliers, tin of smoke (to replenish blown fuses - everybody knows most electrical things run on smoke, when the smoke gets out it's stuffed). – Willtech Aug 24 '18 at 08:41
  • @HarrySvensson I tried to tell my dog this joke but he just looked at me. – Michael Aug 24 '18 at 18:58
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    @Willtech Lol yes. Funny story, wire stretchers exist, for pulling barbed wire so an Albertan apprentice I heard of cut wires too short, so the journeyman decided to demand he find wire stretchers and kept sending him back to keep looking. The kid was a farm kid and knew what wire stretchers were, so eventually he ordered some from UFA. I also know a guy who was sent for a stick of "all thread rigid" as a joke, couldn't find it, so he threaded an entire 10ft stick of rigid conduit. Can of smoke is funny too, as it exists for testing fire alarm equipment. – K H Aug 24 '18 at 21:52
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In the UK system, electricity disconnection for residential customers is a last resort, but they may demand to replace your meter with a "prepayment" one. Either way they can get permission to force entry to your property to do this if necessary.

There is usually a "power company fuse" just before the meter. Removing this disconnects the property.

You can of course just bridge it to get the power back, but that's a criminal offence.

(Some countries have real problems with this system and end up with widespread electricity theft - resulting in high prices, so more people steal electricity. It's a difficult situation to get out of.)

As others have described, power is pooled. In the UK system the retail billing and generation sides can be completely separate. Power can be bought and sold on the "spot market"; the generator company has no knowledge of individual users, just an aggregate figure from the grid authority. There's a complex process by which generators are turned on and off to meet demand, with associated payments.

pjc50
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    I used to be a meter reader for the Dept Water&Power in Los Angeles. The first step (after a whole bunch of unpaid bills) is to switch it off at the meter - and apply a metal ["cable seal"](https://www.google.com/search?q=metal+cable+seal&rls=com.microsoft:en-US:IE-Address&source=lnms&tbm=isch&sa=X&ved=0ahUKEwjYmO_xgobdAhUKBHwKHUskAsIQ_AUICygC&biw=1316&bih=760). If the user removed this and flipped the power back on - that indicated trouble afoot - the next step would be for the DWP to send a special team of _really big men_ to disconnect the property from the power poles. – davidbak Aug 24 '18 at 15:40
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Some modern meters have a remote controlled switch, that can disconnect your power.

The power company can, with a modern meter, remotely monitor your energy usage and cut the power, is the bill isn't paid.

Example: http://products.kamstrup.com
Choose: Electricity, Meters and then OmniPower.

Another example: https://www.landisgyr.com
Choose: Our Offering -> Products -> Devices -> E331/351 FOCUS AXe
This link may take you straight there: https://www.landisgyr.com/product/e331351-focus-axe/

phonetagger
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Peter Karlsen
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  • This would be more useful if you could include a link to a datasheet for a meter with a remote power disconnect. – Transistor Aug 23 '18 at 11:47
  • That's exactly how my meter works. The power company sends a digital signal over the power lines and either reads my meter or opens the relay inside my kWh meter. That signal is sent by interrupting the power from their end near the zero crossing point. – Mike Waters Aug 23 '18 at 19:26
  • I have such a smart meter too. It communicates with the grid operator via GSM, also for the gas meter. They know my consumption and they can turn the power off and on at will. – StessenJ Aug 24 '18 at 14:21
  • These smart meters with an integrated remote controlled switch are being rolled out in France too (called the "Linky"), however, the power company is not legally allowed to cut power remotely due to unpaid bills – Jonas Czech Sep 12 '18 at 12:32
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The electricity company bills you for your usage, they measure this usage at some point. In my house the meter for this is inside my house.

Below this meter there's a sealed box (it has a seal that breaks if you open the box) and that has a big fuse inside it. If I would want to officially be cut off the grid then the utility company could just remove this fuse.

There's a (in my case underground) cable that delivers this power. This cable goes outside my house so the company that manages the delivery of the electrical power will have access to (part of) that cable. In my country the cables go to a distribution point or might be tapped off from a "bigger" cable under the street. Still all in reach of the company.

So for cutting you off there are plenty of options even if the company does not have access to your apartment.

Regarding "your" electricity: there is no electric power generated specially for you. All electrical power is the same. It's all collected on the same system. The company that manages the delivery of the electrical power to your home just measures what comes in (generated by itself, other companies and consumers with solar panels for example) and what goes out (used by you and others).

Everyone adds to and uses from the same "pool of electrical power". That works as it is impossible to determine if the power generated for you is actually delivered to your home. So the company could just say to that "sure we're only delivering your power to your home" as it is impossible for you to determine if that is true or not. And it doesn't matter as power is power.

Bimpelrekkie
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    Many power companies in my country offer the client a choice of source of electricity (nuclear, wind, etc.). So this choice kind of doesn't matter as all power comes from the same "pool"? If I were, for example, against nuclear power, how would paying for wind power make me more ecological since most of my electricity in practice is still probably produced by nuclear plants? – S. Rotos Aug 23 '18 at 10:14
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    @S.Rotos what the 'choice of source of electricity' means is probably that the company promises they will generate or buy at least as much energy from renewable sources as is used by the customers who have chosen that they want renewable energy. If they would have sourced at least that much from renewables anyway (e.g. because it was the cheapest option at certain times) then your individual choice has no effect, but if enough customers choose renewable-only then the companies must buy or generate more power from renewables and less from non-renewables if they are to keep their promise. – nekomatic Aug 23 '18 at 10:58
  • @nekomatic: It's always *no effect*. Power from renewables has zero generation cost, just capital cost. That means, if there is plenty renewable power available, they will sell it to *just anyone*, and if there's not plenty available, they will only sell it to those who pay extra plus a tiny fraction of those who don't pay extra. Either way, paying extra has no effect. – Janka Aug 23 '18 at 13:00
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    @Janka if the retail supplier is not the same company as the generator (as in the UK) then the retailer will pay the generator per kWh for it. If enough customers demand only renewable power then the generator(s) will have to build more of it to meet the demand. I won't say this is the best way of encouraging renewables but it can have some effect. – nekomatic Aug 23 '18 at 15:01
  • In Germany, grid renewables are that much subsidized there is sufficient installed power yet. It's only the wind which is sometimes completely missing — or there is too much. Also, each electrical grid consumer has to pay for it anyway. Why do I say "grid consumer"? Because they had the wacky idea if you go off-grid and make your own electrical power –as many industries considered–, you had to pay that electrical grid/renewables tax **also**. That rule is now into effect only for industries, not private homes because even the greenest greens protested against that lunacy. – Janka Aug 23 '18 at 19:52
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    @S.Rotos When you pay for wind energy, for example, they will take the amount of electricity you use, and they will pay to run the wind generators that much. It doesn't mean the specific electricity you use came from the wind generators, but it doesn't matter because it's all the same (nuclear electricity is not radioactive) and actually it's not possible to measure that. – user253751 Aug 23 '18 at 22:52
  • @Janka Reminds me of the British TV licenses and the Internet. – user253751 Aug 23 '18 at 22:53
  • We have those, too. Seriously. – Janka Aug 23 '18 at 23:01
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    @immibis Oddly, the way you worded that had me picturing them paying to run the wind generators, which generate the wind which turns the windmills which then generate the electricity you just paid for... – Michael Aug 24 '18 at 19:04
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When it happened to me (and my apartment mate, who ought to have been on top of the bills) they pulled the meter off and replaced it with a blank panel, sealed with a tamper-evident tag. This was in the US, PG&E, about 2000 or 2001. This was one of the glass meters with the rotating dials, which were ubiquitous in the US and Canada at that time. At that location there was no external disconnect switch, as I see are common in the DIY shows from other parts of the US.

So, this could vary widely by region, and time. This is just my experience.

(When we paid up they replaced the meter but added a locking collar on it so we couldn't tamper with it to bypass metering.)

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In North America, for residential power, typically pole-mount distribution transformers are used. Those transformers are shared between several houses except in rural areas where the distances would be too great to be economical.

To disconnect service the break has to be made after the transformer, at the low voltage side. That can be done at the pole with a switch or at the meter by taking the meter off, making a change, then putting the meter back on.

Modern smart meters such as the Landis and Gyr Focus AXR-SD can remotely cut off a customer's power by using the RF communications network they use to read consumption data. The base of the meter contains a bistable relay that is driven on and off by a momentary 12V signal. SD here stands for "Service Disconnect". See page 47 in the linked manual.

In an apartment with individual power metering the disconnect would likely take place at the meter. If there is no individual power metering but your electricity is billed separately as a flat sum (perhaps with an adder for A/C) then it would be up to the building managers rather than the power company, and they would break the power in the same way as it would be for maintenance- at a service panel inside or outside your apartment.

Naturally, there are physical and electronic security features that ensure that the power company will know if the meter has been tampered with, and there will be expensive consequences for such actions.

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As several answers have indicated, if you have a so-called smart meter, and your local jurisdiction allows it1, the electricity distribution company (who is responsible for providing power to your house) may be able to remotely disconnect your power if the bill isn't paid. This is done by means of an electrically actuated switch inside the meter itself.

In many parts of the world where smart meters are not (yet) installed, you may have a socket meter, like this:

Socket meter

In this case, power can be disconnected by simply removing the meter. The image below is from a question on DIY.SE, and shows how this works inside the meter box:

Meter socket

The meter inserts into the four metallic "jaws," which send current through the meter for measurement.

When the meter is removed, a blank plate is inserted and locked in place to prevent tampering:

Locked out meter socket

The meter must be re-installed to restore service.

1. I wasn't able to find a comprehensive list of states where remote disconnect is legally permitted, but it is at least allowed in Idaho and Ohio. Wikipedia provides a list of public utility commissions by state which you could use to find your state's commission to contact them and find out if remote disconnect is allowed in your case.

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    They don't need to remove it, they often rotate the meter so it doesn't touch the contacts and put it back in. At least that's how I found it when I moved into a house where the power was shut off. – user71659 Aug 23 '18 at 16:49
  • According to a video (from a guy who definitely had his power disconnected from time to time) sometimes they put insulating caps over the blades. – Spehro Pefhany Aug 24 '18 at 04:46
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It depends. They can break the circuit at the pole feeding your home if you have above ground service. If it is underground they can break it at the transformer distribution box. I suspect with the new modern remote meter reading technology they can cut it at the meter but that is conjecture on my part.

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