How do you say informally when someone steals electricity by tapping from the line illegally?

Juice Jacking or siphoning power, but neither the term nor the action is very common. It's becoming more common for people to "steal" power from their employers, Landlords, or the government to trickle charge electric cars anywhere there's an outlet close enough to a parking space, but I've never heard of it being prosecuted.

Siphoning electricity from the grid Juice jacking from the grid/utility. Leeching from the grid.

He stole my power

In my experience with NA English, there isn’t a commonly used global expression. Some specific actions have specific terms: 1. “Siphoning electricity (illegally)”, or “tapping into the grid” would be terms for connecting your home to the grid without it going through a meter. 2. “Meter tampering” is the process of affecting meter readings (possibly by bypassing the meter to some extent in the main electrical panel of a home). 3. I’ve heard the term “abstracting energy” but that seems more legal, technical, and (for want of a better word) abstract at least here in NA. I think it originates in the UK and maybe it’s more commonly used there?

This… is too specific to have an expression… Also stealing electricity isn’t a thing in a legal sense in basically any English speaking country. Electricity is viewed as a global commodity, it’s not very considerate to get angry at someone for innocently using a charger even if them using it technically added to your electricity bill. Like it’s probably illegal to do it in excessive amounts but doing it at all won’t get you arrested. (I am however not a lawyer and this is ***not*** legal advice)

Cable hooking or power tapping. Neither is as clear or specific as Izinyoka, which I assume you're trying to translate. "Electricity theft" or "stealing electricity" would be the most widely understood ways to say it.

This is so uncommon that there’s not really a standard informal term for it in English. You’d have to explain what exactly the person was doing. Where I live, a person would be considered pretty crazy to tamper with the electric company’s lines. 

Siphoning electricity would be the term I’ve heard in the UK, akin to siphoning fuel from a vehicle as theft. Or more generally you’d just say theft of electricity. It does happen, often landlords who subdivide houses into flats and don’t properly wire individual circuits so tenants end up paying for others use, or people using communal or public power sockets, but there have been cases where people tap into others feeds by rewiring deliberately. There was someone asking about a neighbour taking their leccy on the UK legal advice sub recently. Worthwhile when energy is close to 30p a kWh in the UK. At least when I was at school and perhaps because it made an interesting equation in physics, we were also told about examples of meter fraud involving turning walls into giant capacitors to trick the meter somehow.

Stealing electricity or stealing power.

Barely speak English me no speak Americano neither!

There are no common idioms as it’s not a common occurrence. If it were said naturally it would be something like “stealing electricity by tapping the line”. Apparently in some contexts, and as jargon, the usage is to “abstract electricity” however, this is neither a common idiom nor is it informal.

"Dude there was this guy that tapped into the power line illegally to steal electricity"

I think I would call it “pirating power”.

I believe we call it theft of services in most jurisdictions.

I would say they’re « pirating » it. You’d hear about it with cable service and sometimes electricity.

As others have said, while there is apparently a formal term for this, it’s not something that happens frequently enough that a casual audience would know that terminology. People might call it “poaching.”

"To jack/Jacking." People jacked cable when cable was the main way to watch TV. People jack electricity, and sometimes even network the internet to each other with physical cable today. "To pirate/Pirating." For digital non-cabled sharing outside legal bounds. "To hack/Hacking." Reddit is full of scolds, dunno why they're being so ignorant about this today.

I wouldn’t say there is a common idiom because it’s not that common. I would probably say something like. Stealing electricity. Poaching electricity. Siphoning electricity. Now of these are idioms though, they are directly describing what’s happening.

not everything has a name

Sucking the juice Stealing electricity Tapping the line?

Most Balkan question.

I've heard of jumping or using jumpers. I think technically it's to bypass the metres or something in the circuit. But, it connotes stealing when used to tap illegally

I’ve heard leeching

Tapping the meter?

I don’t know about common idioms, it’s referred to technically and publicly as ‘ meter tampering’ in England. an example may be: ‘The illegal cannabis farm bypassed the electricity meter. The energy company say it is dangerous to tamper with the meter’

Its not a common enough occurrence to have a nickname of any sort.

Curious. Assuming you have an idiom in your native language since you asked.... What does it translate to in English?

He jacked the line and stole power. He diverted power from the grid for his own use.

Not really something that's common, so nothing particular. I guess you could say Leeching/Bumming off the grid? These are more verbs you'd hear when it's someone taking advantage of someone else by using their resources. "Your boyfriend is just leeching off you" "He needs to stop bumming off you" "He tried to bum a smoke"

Stealing electricity “from the pole” or “from the meter.”

You don't say anything. You let the police deal with it.

It’s called weasing the juice.