Short answer: every socket circuit in an event's temporary installation is protected by a 30 mA residual current device, the feed to temporary structures is protected at its origin by a device rated no higher than 300 mA, and the two are coordinated so the smaller one trips first. Article 18 of Turkey's Elektrik İç Tesisleri Yönetmeliği (Electrical Internal Installations Regulation) sets out the same pair: a 300 mA device at main distribution points for fire protection, a 30 mA device at sub-distribution points for life protection. TS HD 60364-7-711, the standard covering temporary installations for exhibitions, shows and stands, applies that logic to the event floor and adds one more rule that catches people out. These installations must be inspected and tested again after each assembly on site. The fact that the same cable set worked perfectly in another venue last week counts for nothing. What follows covers device selection, generator earthing, cable routing, voltage drop, inspection intervals and who actually signs.
What RCD rating do you need?
Two thresholds, two different jobs. 300 mA is the fire protection threshold, cutting the supply at the point where leakage current carries enough energy to ignite installation materials. 30 mA is the life protection threshold, set around the current level at which flow through the human body becomes dangerous. TS HD 60364-7-711 requires all circuits for socket outlets rated up to 32 A, and all final circuits other than emergency lighting, to be protected by a device with a rated residual operating current no greater than 30 mA. Cables supplying temporary structures are protected at their origin by a device rated no higher than 300 mA, and that device should be S type. The delay is the whole point: the 30 mA downstream trips, the main feed stays up. Without that coordination you get the familiar result. One fault at one stand takes the entire hall dark.
Does the installation get retested at every build?
Yes, and this is the sharpest difference between a permanent building installation and an event one. TS HD 60364-7-711 requires temporary installations for exhibitions, shows and stands to be inspected and tested on site after each assembly. Same distribution board, same cables, same crew: if the venue changed, the test is repeated. The standard also expects users to check the installation daily for damage. At a three day trade fair that means walking the full cable route every morning before the doors open. Three questions to put to any supplier at quotation stage. Will the installation be tested once the build is finished, who performs the test, and do we receive the report?
How is the generator earthed?
System earthing should be TN-S or TT. TN-C and TN-C-S arrangements are not considered appropriate for temporary or outdoor installations, because bonding every accessible extraneous conductive part is not realistic on an event site. Where a generator feeds the installation, the star point is connected to a separate earth electrode. The IET's guidance on exhibitions, shows and stands cites BS 7430, the code of practice for earthing, in recommending that an independent earth electrode associated with the local earthing of a generator star point should not exceed 20 ohms. Accessible structural metalwork, truss, the support frame behind an LED wall, stand profiles, is bonded back to the main earthing terminal, and in more than one place where the construction does not guarantee continuity on its own. Minimum bonding conductor size is 4 mm² copper.
How often is the earth measured, and who signs it?
Annex P of Turkey's Elektrik Tesislerinde Topraklamalar Yönetmeliği (Earthing in Electrical Installations Regulation) gives two intervals for non-fixed installations: one year for fixed operating equipment and six months for equipment that moves between sites. Almost all event equipment falls into the second group. A generator is in İstanbul one week and Antalya the next. The Work Equipment Regulation (İş Ekipmanlarının Kullanımında Sağlık ve Güvenlik Şartları Yönetmeliği) sets the periodic inspection of electrical and earthing installations at once a year where the relevant standard gives no interval, and restricts the work to electrical engineers and electrical technicians. Annex P wants the name, title and chamber registration number of the engineer who performed the measurement to appear on the document. An unsigned printout is not a report.
Where do the cables run, and which cables?
Wiring cable should be copper with a minimum cross sectional area of 1.5 mm². Armoured or mechanically protected cable is used wherever there is a risk of damage, and flexible cords are not left unprotected in areas the public can reach. On site that translates into cable ramps, under carpet channel and overhead suspension. Outdoors a degree of protection of at least IP33 is expected, meaning protection against solid objects of 2.5 mm and larger plus resistance to spraying water. Where the building has no fire alarm system, cables should be flame retardant to the BS EN 60332 series and low smoke to BS EN 61034, or enclosed in conduit or trunking offering at least IP4X. There is a number behind all this detail. Figures compiled from İstanbul Fire Department statistics put roughly 22.6 percent of fires in the city between 2013 and 2017 down to electrical faults. The spotlight buried inside a decor piece belongs on that list too, since it is the hottest and most forgotten component on the build.
What changes when the generator sits 80 metres from the stage?
Voltage drops. The Turkish regulation limits percentage voltage drop between the building connection box and the point of use to 1.5 for lighting and socket circuits and 3 for motor circuits. On a temporary system the benchmark holds even where the article does not apply directly, because the physics does not negotiate: voltage drop rises with current and distance and falls as conductor size increases. Double the run and the drop doubles. Go up one cable size and you get it back. The symptoms on site are recognisable. Dimmers behave erratically, moving fixtures reset themselves during focus, LED panel brightness drifts across the wall. Pushing the generator far from the hall to deal with noise is not free, and it means recalculating cable sizes. Decide the generator position with the power plan open, not before it.
Every stand wants its own isolator
This is the clause people skip most often. Each separate temporary structure intended to be occupied by one specific user, whether a vehicle, a stand or a unit, should have its own readily accessible and clearly identifiable means of isolation. The same applies to each distribution circuit supplying an outdoor installation. The reasoning is plain. When smoke comes off a stand at midnight, what you need is the isolator for that stand, not the main switch that kills the whole hall. Labelling is a technical requirement rather than decoration. A note scribbled on the panel door is the one thing nobody can read at two in the morning. The standard also puts a ceiling on supply voltage for these installations: 230/400 V a.c.
Who is responsible for power on site?
BS 7909, the code of practice for temporary electrical systems for entertainment and related purposes, expects a competent person to be named with overall responsibility for the safe installation, testing, operation and dismantling of the system. In Turkey the equivalent sits in employer duties under Occupational Health and Safety Law no. 6331, together with the authorised person who carries out periodic inspections. Three lines in the contract settle it: who builds the installation, who signs the test report, and when the generator and distribution boards were last inspected. On Tales Event builds for sound, lighting and LED screen, the distribution board, residual current protection and earth measurement are part of the installation package. Send us your event date and venue and we will size the power plan against the hall's existing board and your equipment list.
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