Reference
What the law asks of the unit after it is delivered
Four duties that attach to a towable commercial unit once it is working, what each instrument actually says, and how often it says to do anything.
Two of the four state no interval at all.
Each item names the instrument or the regulator's own page it was read from, with the date. It is not legal advice.
Gas work, and who may do it · The electrical installation, and how often it is checked · Whether the trailer needs an annual test · Moving your own waste
Gas work, and who may do it
The Gas Safety (Installation and Use) Regulations 1998, SI 1998/2451 read 2026-09-08
| Regulation 3(1) and 3(2) | Nobody may carry out work on a gas fitting or gas storage vessel unless competent to do so, and the employer or self employed person with control of that work has to ensure it. |
|---|---|
| Regulation 3(3) | An employer may not let an employee carry out work on a gas fitting, and a self employed person may not carry it out, unless they belong to a class of persons approved by the Health and Safety Executive. That approved class is the register operated on the Executive's behalf, which is why the question a site asks is whether the engineer is on it. |
| Regulation 3(8) | The regulations deal expressly with work on a gas fitting in a vehicle, vessel or caravan, and require the installer to ensure so far as is reasonably practicable that the fittings and flues will not contravene the regulations once connected to a supply. |
| Regulation 2(5) | The exclusions here are a self propelled vehicle, a sea going ship, certain vessels, a hovercraft and a caravan used for touring. Each carries its own exception for hiring out in the course of a business. A drawbar trailer built for catering or welfare is none of those things. |
| Regulation 2(4)(d) | Most of the regulations do not apply to temporary installations used in connection with construction work within the meaning of CDM 2015, save regulations 37, 38 and 41 and subject to regulation 3(8). Whether a particular welfare unit standing on a particular site is inside that paragraph is a question about the installation and the site rather than about the trailer, and it is answered by a competent person rather than by a supplier. |
How often. The regulations state no periodic interval for a unit of this kind. What produces an annual certificate in practice is the requirement that work is done by an approved person, together with what an insurer, an event organiser or a principal contractor asks to see before the unit is allowed on. Those are commercial requirements rather than statutory ones, and they are usually the binding ones.
The electrical installation, and how often it is checked
The Electricity at Work Regulations 1989, SI 1989/635 read 2026-09-08
| Regulation 4(1) | All systems shall at all times be of such construction as to prevent danger, so far as is reasonably practicable. |
|---|---|
| Regulation 4(2) | As may be necessary to prevent danger, all systems shall be maintained so as to prevent danger, so far as is reasonably practicable. |
| Regulation 4(3) | Every work activity, including the operation, use and maintenance of a system and work near one, shall be carried out so as not to give rise to danger, so far as is reasonably practicable. |
How often. There is no interval in the regulation. It says maintained as may be necessary, which makes the interval an output of a risk assessment rather than a number to be looked up. A unit that is towed, connected to a different supply every week and washed down daily is not on the same interval as a fixed installation in an office, and the reason to write that down is that the duty falls on the person using it.
Whether the trailer needs an annual test
DVSA, get an MOT for a heavy goods vehicle, bus or trailer read 2026-09-08
| Who needs one | Vehicles built or adapted to form part of an articulated vehicle, semi trailers, horseboxes over 3,500 kg gross, A frame trailers and converter dollies made on or after 1 January 1979, trailers with an unladen weight of more than 1,020 kg that have powered braking systems instead of standard overrun brakes, public service vehicles with more than eight passenger seats, and goods vehicles over 3,500 kg gross. |
|---|---|
| When | A trailer that needs one is usually tested one year after it was first sold or supplied, and annually after that. |
| The line that matters here | The trailer entry is not about weight alone. It is unladen weight over 1,020 kg together with a powered braking system in place of overrun brakes. The braking decision is made in the specification and it decides which side of that line the finished unit lands on. |
Moving your own waste
Environment Agency, register or renew as a waste carrier, broker or dealer read 2026-09-08
| Who must register | A business that transports waste, or buys, sells or disposes of it, or arranges for someone else to. Not registering carries an unlimited fine. |
|---|---|
| The lower tier | Registration is usually free if you only transport waste that you produce yourself, and a lower tier registration does not have to be renewed. That is the case a single operator taking their own waste off a pitch usually falls into. |
| Elsewhere in the United Kingdom | Scotland, Wales and Northern Ireland each register separately, through their own agency. |
How often. An upper tier registration is renewed every three years. A lower tier registration is not renewed, but the Environment Agency has to be told within 28 days if the registered details change.
The annual test line, against our own range
14 of 22 units are over 1,020 kg unladen, and none of them needs a test
The DVSA entry is unladen weight over 1,020 kg together with a powered braking system in place of overrun brakes. The build standard settles the second half: Overrun braking with automatic reverse, on every axle above 750 kg gross. So the weight is reached and the entry is not.
| Unit | Unladen weight | Against the entry |
|---|---|---|
| Welfare 420 | 2,350 kg | Overrun braked, so outside the entry |
| Welfare 360 | 1,950 kg | Overrun braked, so outside the entry |
| Catering 500 | 1,750 kg | Overrun braked, so outside the entry |
| Pizza 500 | 1,750 kg | Overrun braked, so outside the entry |
| Bar 500 | 1,750 kg | Overrun braked, so outside the entry |
| Washroom 500 | 1,750 kg | Overrun braked, so outside the entry |
| Shower 500 | 1,750 kg | Overrun braked, so outside the entry |
| Welfare 300 | 1,600 kg | Overrun braked, so outside the entry |
| Kitchen 400 | 1,350 kg | Overrun braked, so outside the entry |
| Pizza 400 | 1,350 kg | Overrun braked, so outside the entry |
| Barbecue 400 | 1,350 kg | Overrun braked, so outside the entry |
| Washroom 400 | 1,350 kg | Overrun braked, so outside the entry |
| VIP 400 | 1,350 kg | Overrun braked, so outside the entry |
| Shower 400 | 1,350 kg | Overrun braked, so outside the entry |
Not covered here
Four things outside this reference
Registering the food business is a separate duty with its own timing, at least 28 days before trading in England, Wales and Northern Ireland. It is on the food hygiene law page rather than repeated here.
Street trading consent, market pitch rules and event licensing come from the local authority or the organiser rather than from an instrument, and they differ street by street. No page can answer them in general and this one does not pretend to.
Insurance is not a statutory duty for a trailer standing still, and what an insurer asks for is a contract question.
This is Great Britain, and it is not legal advice. Where a paraphrase here and the instrument disagree, the instrument is right. Tell us and it is corrected.
Citing this
MODUWRIGHT. "What the law asks of the unit after it is delivered." Read 2026-09-08. http://127.0.0.1:8812/after-delivery
Free to quote, reproduce or set as reading, in whole or in part, on one condition: name the source and link to it. If a row is wrong, tell us and it is corrected.
Set this as an exercise
Environmental health, hospitality business, events- Two of the four instruments on this page state no periodic interval at all. Identify them, and explain what actually produces an annual certificate in practice and why that is a commercial requirement rather than a statutory one.
- Regulation 2(5) of GSIUR 1998 excludes a self propelled vehicle and a touring caravan. Explain why a drawbar trailer built for catering is caught, and what regulation 2(4)(d) then does to a welfare unit standing on a construction site.
- Fourteen of the 23 units are over 1,020 kg unladen and none of them needs an annual test. Explain the second half of the DVSA entry that decides this, and name the specification decision that settles it.
Free to set as coursework, print, adapt or put on a slide, on one condition: name the source and link to it. What else is free to teach from.
What the law requires the unit to contain is on food hygiene law for a mobile unit and welfare facilities under CDM 2015. What may tow it is on towing limits.