Temporary installations at fairgrounds and events (§740) — mandatory 30mA RCD

Note in advance: the existing guide on this site with the slug 740-greenhouses in fact covers, despite its name, §705 content on agricultural and horticultural installations — this article covers the actual §740: temporary installations at fairgrounds, amusement parks and circuses. The two subjects have nothing to do with each other beyond the coincidentally similar section numbers.

Scope

§740 (based on IEC 60364-7-740) sets requirements for movable or temporary electrical machines and structures at fairgrounds, amusement parks, circuses and similar events: attractions, stalls, stages, lighting installations and the associated wiring that are repeatedly set up, used and dismantled again at changing locations.

Mandatory RCD protection on every final circuit

Every final circuit supplying lighting, socket-outlets up to and including 32A, or portable equipment (via a flexible cable up to 32A) must be protected by an RCD with I∆n ≤ 30mA. This applies without exception to virtually all final circuits within the scope of §740 — the temporary nature and the exposure to the public and weather conditions make this additional protection necessary, regardless of whether a comparable circuit in a fixed installation would also require an RCD.

Voltage limit

The rated supply voltage of installations within the scope of §740 is limited to 230/400V AC or 440V DC — higher voltages fall outside the scope of this section and require additional measures specifically designed for that situation.

Note: this article gives the core requirements of §740. The practical implementation (number and type of distribution boards, cable type and routing, earthing of attractions) varies considerably per event and is not covered in detail in this article.

Practical relevance

When setting up a fairground attraction or an event stage, it is important to verify that every final circuit — even one that might be permitted without an RCD at a fixed location — is actually supplied via a 30mA RCD, since the temporary setup, exposure to moisture and the presence of large numbers of the public increase the risk of indirect contact compared with a fixed installation.

Common mistakes

Using a final circuit without a 30mA RCD because a comparable circuit in a fixed installation would also be permitted without one — the requirements of §740 are stricter than the regular requirements precisely because of the temporary and public nature of the installation.
Confusing this guide with the existing 740-greenhouses guide — that guide covers a completely different subject (agricultural/ horticultural installations, §705), despite the similar name.
Assuming a higher voltage than 230/400V AC / 440V DC without the additional measures that would be required outside §740 for that.