The five safety rules and who is allowed to do what

🌐 Machine-translated page. The German version is authoritative.

Why electricity is so dangerous

You can’t see electricity, you can’t hear it, you can’t smell it. From about 10 mA your muscles cramp – your hand can no longer let go of the conductor. From about 30 mA there is a risk of Herzkammerflimmern (ventricular fibrillation), sometimes after just a few hundred milliseconds. For comparison: an LED lamp draws 35 mA. The body’s resistance with dry skin is around 1 000 Ω – at 230 V that means more than 200 mA flowing through you. That’s why the order of the five rules isn’t a ritual, it’s a survival strategy.

On top of that comes the Lichtbogen (electric arc): in a short circuit caused by a tool touching a Sammelschiene (busbar), temperatures of several thousand degrees are generated – severe burns even without any current flowing through your body.

The five safety rules – step by step

The rules come from DIN VDE 0105-100 and apply before any work on an electrical installation, in the spannungsfreien Zustand (de-energized state). Follow the order – when establishing it, go from 1 to 5; when switching back on, go backwards from 5 to 1.

1. Freischalten (disconnecting from the power supply)

Switch off the installation or the part of the installation allpolig (all poles): Leitungsschutzschalter (LS-Schalter) off, RCD off, Hauptschalter (main switch) off, SLS off if applicable, pull the fuse. “Allpolig” means: the N (Neutralleiter, neutral conductor) must also be disconnected where that is intended. Just flipping the light switch is not Freischalten.

2. Gegen Wiedereinschalten sichern (securing against switching back on)

Nobody else may accidentally switch it back on. Means: a Sperrelement (locking device) on the Leitungsschutzschalter, a Vorhängeschloss (padlock) on the Hauptschalter, take the pulled fuse with you, and a Verbotsschild (prohibition sign) reading “Do not switch – work in progress”. A note is not a safeguard. In buildings that aren’t yours: find out who else has access.

3. Spannungsfreiheit feststellen (verifying absence of voltage)

Use a zweipoliger Spannungsprüfer (two-pole voltage tester) (according to DIN EN 61243-3) to check all conductors: L1, L2, L3 against N, against PE (Schutzleiter, protective conductor) and against each other. Before and afterwards, test the tester on a known voltage – a defective tester shows nothing even on a live installation. Phase tester screwdrivers (“Lügenstift”, liar’s pen) are not approved for this.

4. Erden und Kurzschließen (earthing and short-circuiting)

Connect all conductors to earth and to each other. If the installation does become live anyway – through back-feeding, a switching error, photovoltaics – the protective device trips immediately. In the Niederspannung (low voltage range, up to 1 000 V) this rule is only necessary if back-feeding is possible (PV system, emergency power, overhead line) – usually not in residential wiring. In high voltage it is always mandatory.

5. Benachbarte, unter Spannung stehende Teile abdecken oder abschranken (covering or barricading adjacent live parts)

What could not be disconnected – the Zuleitung (incoming feeder) in front of the Hauptschalter, the Sammelschiene in the Zählerschrank (meter cabinet) – is covered with isolierende Abdeckungen (insulating covers) (cloths, moulded parts, protective plates) or made unreachable by barricading.

Only when all five steps are done does the work begin. When you leave and come back: repeat step 3.

Working on live equipment

Basic principle: No work is done on live equipment. Exceptions (DIN VDE 0105-100) require special training (AuS), special tools and protective equipment, and a written instruction. For Azubis (apprentices) the rule is: never. Even “quickly swapping” a Steckdose (socket outlet) while live is forbidden and counts as a serious mistake during the Ausbildung (apprenticeship).

The only things allowed on live equipment are Messen und Prüfen (measuring and testing) with devices suitable for that purpose (measuring category CAT III for distribution boards, CAT IV for the Hausanschluss (service connection)) and Bedienen (operating).

Who is allowed to do what? Elektrofachkraft, EuP, Laie

The DGUV Vorschrift 3 and DIN VDE 0105-100 distinguish three groups of people:

Person	Definition	May
Elektrofachkraft (EFK) (qualified electrician)	completed training in an electrical profession (or equivalent) plus experience and knowledge of the standards	work independently on electrical installations, install, test and release installations
Elektrotechnisch unterwiesene Person (EuP) (electrically instructed person)	instructed by an EFK for specific, recurring tasks	only these tasks, under the direction and supervision of the EFK
Elektrotechnischer Laie (electrical layperson)	everyone else	operate devices, switch a fuse back on, press the test button on the RCD – not connect cables, swap socket outlets, open distribution boards

The Azubi is not an Elektrofachkraft – only with the Gesellenbrief (journeyman’s certificate). During the Ausbildung you work under supervision of an EFK who carries the responsibility. That’s not distrust, it’s the law.

Die verantwortliche Elektrofachkraft (vEFK) (the responsible qualified electrician)

In companies, a verantwortliche Elektrofachkraft (responsible qualified electrician) carries the technical and supervisory responsibility: they decide who may do what, and organize tests and instruction sessions. In a craft business, this is usually the Meister (master craftsman).

§ 13 NAV – the boundary with the grid operator

The Niederspannungsanschlussverordnung (NAV) (Low Voltage Connection Ordinance) regulates the relationship between the Netzbetreiber (grid operator) and the connection owner. § 13 says: work on the electrical installation behind the Hausanschluss may only be carried out by a company that is registered in the Installateurverzeichnis eines Netzbetreibers (installer directory of a grid operator). This affects:

Hausanschlusskasten (HAK) (service connection box) and main line
Zählerplatz (metering point): building the Zählerschrank, installing the SLS, wiring the Zählerfeld (meter field)
Inbetriebsetzung (commissioning) of new installations and registration with the Netzbetreiber
Registration of PV-Anlagen (PV systems), Wallboxen (wallboxes), Wärmepumpen (heat pumps)

The meter itself is installed and verplombt (sealed) by the Netzbetreiber or Messstellenbetreiber (metering point operator). Breaking seals is forbidden – even for the electrical company, unless agreed otherwise.

Only a company with a verantwortliche Elektrofachkraft with Meister qualification (or equivalent) gets into the Installateurverzeichnis – the real reason why the Meister is in such high demand in the electrical trade.

Persönliche Schutzausrüstung (personal protective equipment) and tools

Isoliertes Werkzeug (insulated tools) (VDE tools, tested to 1 000 V, double triangle symbol).
Zweipoliger Spannungsprüfer, tested regularly.
Schutzbrille (safety glasses) when working on distribution boards and Sammelschienen (arc flash).
Sicherheitsschuhe (safety shoes) on construction sites; helmet if needed.
No rings, watches, chains – no metal on your body.

Test yourself

🧠 Test yourself

1. In what order are the five safety rules applied?

2. What is used to verify the absence of voltage?

3. Is an Azubi allowed to work independently on an electrical installation?

4. Who is allowed to build a Zählerschrank and register the installation with the grid operator?

5. From what current through the body is there a risk of Herzkammerflimmern?