Author: Marcin Ruta

Main topic: EN 50110: Key Requirements for Work on Electrical Installations   

Standards and regulations mentioned: EN 50110

Reading time: 10 min

Introduction to EN 50110: Key Requirements

The latest edition, PN-EN 50110-1:2024-04 “Operation of electrical installations – Part 1: General requirements”, is the cornerstone document for the safe operation of electrical installations across Europe. As a European Norm (EN), it sets out the minimum requirements and procedures for any work on, with, or near electrical installations. 

In this article I walk through its most important points – the ones everyone involved in operating electrical installations should know. 

Why does EN 50110 matter so much? 

The provisions of EN 50110 have been carried over into Polish law – specifically the Regulation of the Minister of Energy of 28 August 2019 on occupational health and safety when working with energy equipment (Polish Journal of Laws, item 1830). 

The 2024 edition covers some very important areas of electrical work, the standard itself is only about 50 pages long. The Polish regulation is just 11 pages long. That’s a short read, and I can promise you it clears up a lot. 

If you want to go further, take a look at EN 50110-2. It collects the national annexes showing how other EU countries have adapted the standard – an interesting read, given how differently it has been implemented across Europe. 

The main objectives of the standard are to: 

• Establish uniform electrical safety guidelines, 
• Minimise the risk of electrical accidents, 
• Standardise basic working procedures, 
• Protect workers’ lives and health

What can we learn from it?  

EN 50110 has been partly absorbed into various national regulations and into other IEC and EN standards. Reading all of them tells you more about national requirements – but reading EN 50110 itself gives you a clear picture of the guidelines on: 

• basic terms and definitions, 
• personnel qualifications, 
• organisation of electrical work, 
• defining and determining hazardous zones, 
• requirements for safety measures, 
• descriptions of and recommendations on electrical hazards (electric shock, arc flash). 

Key definitions   

1. Skilled person – someone with the training, knowledge and experience to carry out electrical work safely. (In Poland this is very clearly defined in the regulations covering qualification requirements and authorisations), 

2. Live working zone – the space where live work is directly carried out. 

3. Vicinity zone – the space surrounding the live working zone, around electrical equipment, with different levels of hazard. 

3. different levels of hazard. 

This is a good place to quote the EN 50110 guidance on working zones: 

1. D_L – distance defining the outer limit of the live working zone, 
2. D_V – distance defining the outer limit of the vicinity zone. 

A real-world example 

The photo below shows a section of a 415 V AC main switchboard. The outgoing feeder sections don’t achieve even the minimum IP2X degree of protection, exposing the electrician to both electric shock and arc-flash burns. 

Because of the switchboard design alone, practically every switching operation here counts as particularly hazardous work. A trained eye will spot straight away that the minimum 30 cm distance (D_L) can’t be maintained – and realistically it should be much larger once arc-flash hazards are taken into account. More on that in upcoming articles. 

Distance tables 

Table 1, EN 50110-1 – Estimated values for distances D_L and D_V 

Nominal system voltage UN (kV RMS)	DL – outer limit of live working zone (mm)	DV – outer limit of vicinity zone (mm)
≤ 1	no contact	300
3	60	1 120
6	90	1 120
10	120	1 150
15	160	1 160
20	220	1 220
30	320	1 320
36	380	1 380
45	480	1 480
60	630	1 630
70	750	1 750
110	1 000	2 000
132	1 100	3 000
150	1 200	3 000
220	1 600	3 000
275	1 900	4 000
380	2 500	4 000
480	3 200	6 100
700	5 300	8 400

Note 1: intermediate values of D_L and D_V may be determined by linear interpolation.  

Note 2: the values in Table 1 are intended as guidance for future harmonisation between countries. 

And here is the corresponding table from the Polish Journal of Laws 2019, item 1830, defining the minimum clearances in air that mark the outer limit of each working zone: 

Table 2, Polish Journal of Laws, item 1830 – Estimated values for live working, vicinity zones   

Nominal voltage of equipment or installation (kV)	Live working (mm)	Work in the vicinity of live parts (mm)
≤ 1	no contact	300
3	60	1120
6	90	1120
10	120	1150
15	160	1160
20	220	1220
30	320	1320
110	1000	2000
220	1600	3000
400	2500	4000
750	5300	8400

Personnel requirements 

EN 50110 itself doesn’t set requirements here – it leaves them to national law. That makes sense, since many European countries already regulate this area in detail. Where no such national rules exist, the standard’s own guidance is a solid fallback. 

In Poland, this area is governed by Journal of Laws item 1830 along with a number of other regulations, which define: 

• persons with designated functions (duty holders), 
• authorised persons, 
• qualified (certified) persons, 
• employer responsibilities, 
• training requirements, 
• requirements for obtaining and verifying qualifications. 

For comparison, here is how EN 50110 divides duties and defines areas of responsibility:  

Table 3, EN 50110 Annex B.1.1 – roles and responsibilities 

Role	Responsibility
a) Installation manager (IM)	Overall responsibility for the electrical installation, 24/7
b) Operation controller (OC)	Responsibility for the installation at the work location – to be documented
c) Work controller (WC)	Responsibility during the work activity – to be documented
d) Worker (W)	Member of the working team

The five safety rules

1. Disconnect completely and isolate (visible isolating gap), 

2. Secure against reconnection (e.g. a LOTO system), 

3. Verify that the installation is dead, 

4. Carry out earthing and short-circuiting (where required), 

5. Provide protection against adjacent live parts (i.e. shield or barrier any other parts of the circuit that remain live). 

Organisational requirements 

• Written work instructions / permits (where required), 
• Designation of persons with specific functions, 
• Risk assessment before work begins, 
• Use of personal protective equipment. 

EN 50110 also gives clear guidance on the basic principles of carrying out electrical work – something that’s far less obvious when you read the national regulations alone. 

What the accident statistics say 

It’s worth looking at data from Statistics Poland (GUS). In 2021 there were 68,777 workplace accidents in total, of which 2,261 were classified as “contact with electric current, temperature, hazardous substances and chemical preparations” – a category that, admittedly, covers more than just electrical accidents. 

Open question: the 2020 category value in the original repeats the 2020 total and should be checked against the GUS source. 

Table 4, accident statistics (GUS)  

Year	All accidents	Contact with electric current, temperature, hazardous substances and chemicals
2022	66,606	2,204
2021	68,777	2,261
2020	62,740	62,740 (to verify)
2019	83,205	2,914
2018	84,304	3,009
2017	88,330	3,065
2016	87,886	2,820
2015	87,622	2,877
2014	88,641	2,781
2013	88,267	2,827
2012	91,000	2,966
2011	97,222	3,202
2010	94,207	3,350

Looking at the recorded causes, inadequate work organisation and improper worker behaviour accounted for more than 60% of all causes. That’s exactly why it’s so important to understand that proper procedures for electrical work exist – and that they make a real difference in protecting people from the hazards of electrical installations.

Summary 

EN 50110 is a comprehensive set of guidelines that: 

• define safe working procedures, 
• protect workers’ lives and health, 
• standardise the approach to electrical safety, 
• reduce the risk of accidents.