Firstly, let us say that neon signage is incredibly safe to use – providing it is well looked after and treated with respect. For more than 100 years neon has been a go-to signage and is now more reliable and safe than ever before.
In the past few weeks the topic of whether a neon sign requires a fire-fighters switch has popped up several times from new customers – so let us give a technical answer…
Any permanent, non-portable, high voltage neon sign over 100w (e.g max 8kv/18ma), will require a fire-fighters switch or connecting to a fire circuit.
Fire-fighter switches are not always required. When considering the requirement, we need to look at the relevant regulations and
these are found in the IET Electrical Regulations.
A Fire-fighter’s switch shall be provided in the low voltage circuit supplying:
1: Outdoor lighting installations operating at a voltage exceeding low voltage and…
2: Indoor discharge lighting installations operating at a voltage exceeding low voltage.
For the purposes of this regulation an installation in a covered market, arcade or shopping mall is considered to be an
outdoor installation. A temporary installation in a permanent building used for exhibitions is considered not to be an exterior
This requirement does not apply to a portable discharge luminaire or to a sign of a rating not exceeding 100w and fed
fro a readily accessible socket-outlet.
A “portable” luminaire (e.g. an art piece) can be of any wattage or voltage and does not require a fire-fighter’s switch.
- A sign powered by multiple low voltage transformers (990v)
does not require a fire-fighter’s switch.
- A sign of less than 100w fed from a readily accessible socket
does not require a fire-fighter’s switch.
- A non-portable sign over 100w requires a fire-fighter’s switch.
So what does 100w allow us to have?
This is dependent on the amount of mA (Milliamps) being passed through the tubes and the voltage required for the installation.
When working out wattage there are two methods, one is the apparent power (expressed as Volt Ampere) and the other is the
Real power (Watts).
Volt Ampere is worked out with the following equation from Ohm’s Law:
P(Watts) = V(Volts) x I(Amps)
However this is not the Real power in watts that is obtained, it is actually Volt-Ampere’s which is not the same thing.
Real power is worked out by multiplying VA (Volta-Ampere) x Power Factor (cosφ) which for wire wound transformers is 0.5, this
results in a much lower wattage. With this in mind anything up to and including the following transformers should be able to be
used, as their Real power is less than 100w when running:
Wire Wound Transformer:
6kV 25mA running at 95 watts.
8kV 18mA running at 95 watts.
8kV/ 20mA running at around 95% of full capacity. Less load uses less power. Installations should be individually checked when
running, as cabling and other factors can affect the efficiency. When a fire-fighter’s switch is required the regulations state:
537.6.2 – Every exterior installation covered by regulation 537.6.1 in each single premises shall wherever practicable be controlled by a single fire-fighter’s switch. Similarly, every internal installation covered by Regulation 537.6.1 in each single premises shall be controlled by a single fire-fighter’s switch independent of the switch for any exterior installation.
537.6.3 Every fire-fighters switch provided for compliance with Regulation 537.6.1 shall comply with all the relevant
requirements of the following items (i) to (iv) and any requirements of the local authority:
(i). For an exterior installation, the switch shall be outside the
building and adjacent to the equipment, or alternatively a
notice indicating the position of the switch shall be placed
adjacent to the equipment and a notice shall be fixed near
the switch so as to render it clearly distinguishable.
(ii). For an interior installation, the switch shall be in the main
entrance to the building or in another position to be agreed
with the local fire authority.
(iii). The switch shall be placed in a conspicuous position,
reasonably accessible to fire-fighters and, except where
otherwise agreed with the local fire authority, at not more than
2.75m from the ground or the standing beneath the switch.
(iv). Where more than one switch is installed on any one building,
each switch shall be clearly marked to indicate the installation
or part of the installation which it controls.
In short, internal and external neon signs should have separate fire-fighter switches, these should be ideally placed next to the sign that it controls or in the main entrance of the building, if not then a sign saying where the switch is should be provided along with a label for the switch. The switch should be no higher than 2.75m from the floor. Due to the age of the regulation and the fact is has not been updated for quite some time, It is also possible to connect into an alarm circuit that switches off when a fire is detected, this should be confirmed as acceptable by the local fire authority.
The reason fire-fighter switches are required is that when spraying water over high-voltage installations it allows the voltage to travel up the water being sprayed, it is a safety feature for the fire-fighters should they ever be required. It is not the fact that a neon sign is more likely to cause a fire, as when installed correctly a neon sign is just as safe as any other electrical installation or appliance.