Testing electrical tools (NEN 3140 work equipment)

Electrical tools, extension leads and appliances are work equipment. You test them periodically, according to the working method of NEN 3140 and the European testing standard NEN-EN 50699. There is no fixed interval: you set one based on risk, and once a year counts as the safe minimum. You record every test in a register.

The duty is set out in article 7.4a of the Arbobesluit (Dutch Working Conditions Decree) . Work equipment that can deteriorate must be tested “as often as is necessary to guarantee its good condition” (zo dikwijls dit ter waarborging van de goede staat noodzakelijk is). The Arboportaal (Dutch working conditions portal) describes once a year as the safe minimum. For the fixed installation, there is a separate NEN 3140 inspection.

In SCIOS terms, a test of tools is called a Scope 9 test. If you have it tested externally, choose a company that is certified for Scope 9.

Which standards apply to testing electrical tools?

Three standards play a role. NEN 3140 governs the management: who is responsible, how you set intervals and how you record. The two European standards describe the testing itself.

Standard	What it covers	When do you use it?
NEN 3140:2011+A3:2019	Safe management of installations and work equipment	Always: organisation, intervals, recording
NEN-EN 50699:2020	Recurring (periodic) testing of electrical equipment	For the periodic test
NEN-EN 50678:2020	Testing after repair	After every repair, before the tool goes back into use

NEN-EN 50699 applies to equipment connected to a final circuit, from above 25 V AC and 60 V DC up to 1,000 V AC and 1,500 V DC, at currents up to 63 A. The Dutch edition is in English.

How often must you test electrical tools?

The standard gives no figure in months. You, or your installation responsible person, set the interval through a risk assessment. Look at four things: how often the tool is used, where, by whom, and how great the chance of damage is.

In addition, always test outside the fixed interval after a repair, after a drop or after getting wet, and after a long period out of use. Article 7.4a, paragraph 4, requires that.

Example of a testing schedule

A fictional installation company with 15 fitters records this. The intervals are their own choice, not a requirement from the standard.

Category	Examples	Interval	Justification
Heavy use on the building site	Hammer drills, angle grinders, cable reels, site lamps	Every 6 months	Daily use, dust, moisture, often dropped
Use in the workshop	Pillar drill, battery chargers, extension leads	Yearly	Dry, fixed place
Office	Laptop chargers, coffee machine, printers	Every 3 years	Low risk, hardly moved
After repair	All	Immediately, before use	NEN-EN 50678

In addition, have users give a quick check of cable, plug and housing themselves before each use. That catches damage between two tests.

What does testing electrical tools involve?

A test consists of a visual check, measurements and a function test. Which measurements are needed depends on the protection class of the appliance.

Step	What is checked	Reject for example
Visual check	Cable, plug, housing, strain relief, rating plate	Torn sheath, loose plug
Protective conductor (class I)	Resistance of the earth connection	Resistance too high, or a break
Insulation resistance	Insulation between live parts and the housing	Value too low
Leakage or touch current	Current that can leak away through the housing	Value above the limit in the standard
Function test	Does the appliance work, and does it switch off properly?	Switch sticks

Who may test electrical tools?

The Arbobesluit only states: a competent person, legal entity or institution. Within NEN 3140, that is someone with an appointment for testing work equipment, who has the right measuring equipment. Record in the appointment which appliances they may test. See appointing VPs and VOPs.

If you do not test yourself, you hire a testing company. A company with a SCIOS certificate for Scope 9 works to a fixed method, which makes the report stronger for clients. For what that scope involves, read SCIOS Scope 9. For what a testing officer (keurmeester) must be able to do, see NEN 3140 testing officer.

Example of a testing register

According to paragraph 6 of article 7.4a, you must have written proof of the tests at the workplace, either digital or on paper. A register can be as simple as this:

ID	Description	Class	Location	Tested on	By	Result	Next test
G-014	Bosch hammer drill	II	Van 3	2 October 2026	P. Vos (VP)	Good	2 April 2027
G-022	Cable reel 25 m	I	Van 3	2 October 2026	P. Vos (VP)	Rejected, sheath damaged	Replaced
K-003	Coffee machine	I	Canteen	15 January 2026	Testing company	Good	15 January 2029

A testing sticker with the date and the next test is useful on the shop floor, but it does not replace the register. The sticker shows that something has been tested. The register proves when, by whom and with what result.

What does the auditor or inspector want to see?

The checklist for the VCA workplace inspection includes a valid testing sticker as a fixed checkpoint. A VCA auditor reviews your testing system and records against the requirements for testing work equipment. Make sure you can show:

A complete register, including tools of subcontractors used on your job
Justified testing intervals per category
What happened to rejected equipment
The appointment of who tests

Common mistakes in testing electrical tools

Forgetting battery tools. The charger is an electrical appliance and must be tested.
Stickers only, no register. After an accident, the Netherlands Labour Authority wants to see the history.
Not testing after repair. Every repair requires a test according to NEN-EN 50678.
Leaving rejected tools in the van. Take them out of use immediately and label them.
The same interval everywhere. A laptop charger and an angle grinder on a building site do not carry the same risk.

What does testing electrical tools cost?

What	Indication
Hand tools and small appliances	Approximately €6.50 to €11.50 per item, depending on the number
Heavier machines on 400 V	Approximately €17.50 per item
Minimum charge for a visit on site	Approximately €225

These are indications from one inspection company. Prices differ per provider. If you have all appliances ready in one place, you save time and money. More on NEN 3140 inspection and SCIOS inspection costs.

Frequently asked questions about testing electrical tools

Must I also test the coffee machine and microwave in the canteen?

Yes. The Arbowet (Dutch Working Conditions Act) counts all appliances used at the workplace as work equipment. The risk is lower, so a longer testing interval is usually justifiable.

Must new tools be tested?

New tools meet the product standard when they are delivered. Still, record them straight away in your register, with a date for the first periodic test. Many companies carry out a brief visual check on receipt.