At a glance
| Ref | Decide | Why it matters | Ask the supplier for |
|---|---|---|---|
| 1 | Where the supply comes from | A floor box, a wall box or a battery decides the cable route and who connects it. | A route drawing from the supply point to the module. |
| 2 | Mains, low voltage or both | Mains-voltage items sit inside the electrical safety regulations; a USB-only module still needs a power supply. | A rating plate and the supply voltage. |
| 3 | Cable protection and strain relief | Cords in a moving or sat-at table are pulled, trodden on and kicked. | A drawing showing clamps and where the cable is fixed. |
| 4 | Cut-out in the top | Stone, glass and veneered tops are weakened by openings and may be tested before cutting. | Cut-out size, edge treatment and the top thickness it was designed for. |
| 5 | Heat | Power supplies warm up and sit in closed spaces. | A statement of operating temperature and the clearance round the unit. |
| 6 | Access | A failed module should come out without lifting the top. | An access panel or a module that can be reached from above. |
| 7 | Spills and cleaning | Restaurant tops are wiped and drinks are spilt. | The protection rating of the module as sold, and the cleaning guidance. |
| 8 | Documents | Someone has to be the manufacturer of the finished piece. | Declaration of conformity, instructions, markings and the test evidence behind them. |
Example decision list. No electrical values are given on this sheet: they belong to the electrician and the standards named below.
The route, from supply to module
Draw the route before choosing the module. A boardroom table normally takes its supply from a floor box under the table; a restaurant table may take it from a wall box and a trunking run, or from a battery. Each route changes the cable path, the leg or rail that carries it, and who is allowed to connect it. In the drawing the cable rises inside a leg, passes along a channel in the rail and meets the module through the top.
Two points are worth fixing early. First, the cable must be held where it enters the furniture, so that a pull on the flex is taken by a clamp and not by the terminals. The IET’s article on electrical fixtures in furniture (Wiring Matters, autumn 2010) records the draft IEC proposal for furniture wiring as asking for cables to be protected against tension and torsion, with strain relief at the points of entry and near connections, and for any wiring that moves to be flexible cable. That was a draft proposal in 2010: read it as the direction of travel, not as a current requirement. Second, leave a slack loop where the table can move, for example where a leaf extends or a top lifts.
What the rules and standards cover
Three layers apply, and different people carry each one.
- The building installation. The fixed wiring up to the floor box or the plug is the electrical installation, normally designed and tested under BS 7671 by the electrician. The IET article notes that BS 7671 covers the fixed installation to the point of connection of current-using equipment, and that furniture connected by a plug and socket is outside it.
- The furniture and the module. The IET article describes BS 6396:2008 as the standard for electrical systems in office and educational furniture, applying to single-phase systems up to 250 V a.c. connected by a 13 A fused plug and socket to BS 1363, and says it makes provision for routing cables through the furniture. It added that for purpose-made items such as cupboards and lecterns no standard existed in 2010 and that the practices of BS 7671 could be applied. Edition history matters: search listings show BS 6396:2008 superseded by an amended 2015 version and a later edition, with records that disagree about the latest. Confirm the current edition before you cite it.
- The product as supplied. The Electrical Equipment (Safety) Regulations 2016 (SI 2016/1101, regulation 3) apply to equipment designed for 50 to 1,000 V a.c. or 75 to 1,500 V d.c. and set safety objectives in Schedule 1: protection against contact, no dangerous temperatures, insulation suited to foreseeable conditions, and resistance to expected mechanical and environmental influences. Plugs and socket-outlets for domestic use are excluded from those Regulations, and are dealt with under separate plug and socket regulations. Whoever puts a finished table with mains equipment on the market has to be able to show the paperwork, so the question for a specifier is who that is.
A USB-only module still has a mains power supply somewhere. Ask where it is and what it is rated for, not only what comes out of the top.
Heat, spills, access and cleaning
Four things go wrong in service. The power supply under the top warms a closed space, so leave clearance and say so on the drawing. Drinks reach the module, so ask for the protection rating of the module as sold and for what the cleaning instructions allow (see IP and IK ratings explained). Cut-outs in stone, glass or thin veneer weaken the top and change its edge, so size them with the fabricator and cross-check table top thickness, overhang and span and glass shelves and table tops. And the module must be reachable: a removable panel in the rail, or a module that lifts out from above, saves a table being turned over in a dining room.
Keep power and data apart inside the table. The IET article points out that data cables are often rated only for extra-low voltage and quotes the BS 7671:2008 rule on separating circuits of different bands. That regulation number and edition are old, so leave the separation detail to the electrician and ask for a drawing that shows it.
Papers to ask for before you approve
- A route drawing from the supply point to the module, with the clamps, slack loop, access panel and clearances marked.
- For each power or data module: the supplier’s declaration of conformity, instructions, rating plate and the standards the supplier says it was tested to.
- For the finished table: who is named as the manufacturer in the paperwork, and what evidence they hold. The studio coordinates manufacture through partner workshops; the responsible party is agreed in the contract and is not decided by this sheet.
- A site test and inspection record from the electrician for the supply to the table, and a handover note on how to isolate it. See handover and O&M pack.
If the table also carries lighting or a display, take the matching sheet: pendants over bars, tables and islands covers the lamp above, and boardroom and meeting table sizing covers the table itself.
Specification wording
Paste into your schedule or specification and replace anything in [square brackets] with your own figures. Wording is a starting point: your specification governs.
Table to be supplied with [power and data modules, number [ ]] fed from [a floor box at the position shown on drawing [ ]]. The supplier is to provide a route drawing showing cable path, strain relief at each entry point, a slack loop of [ ] mm where parts of the table move, and the clearance round any power supply of [ ] mm.
Cut-outs for modules to be [ ] mm by [ ] mm with edges treated as shown on the shop drawing, in a top of [ ] mm [timber / stone / glass]. Each module to be removable [from above / through an access panel [ ] mm by [ ] mm in the rail] without lifting the top.
Power and data modules to be supplied with the supplier’s declaration of conformity, instructions and rating plate, and the standards relied on to be listed. The finished table to be handed over with a named responsible manufacturer, a schematic of the internal wiring, and a test record for the supply by a competent electrician. Values and protection to be set by [the project electrician] to the current edition of BS 7671.
Terms used on this page
- BS 7671
- The UK standard for electrical installations in buildings; it governs how fittings are fixed, wired, protected and tested on site.
- Floor box
- A box set in the floor, with a lid, that gives a table or seat a power and data connection from the building’s installation.
- Strain relief
- A clamp or fitting that holds a cable where it enters equipment, so a pull on the cable is taken by the clamp and not by the connections.
- Grommet
- A lined hole or ring in a table top that lets cables pass through and protects them from the cut edge.
- Declaration of conformity
- A document in which a manufacturer states that a product meets the requirements that apply and lists the standards relied on.
- Pop-up module
- A power or data unit that sits flush in a table top and rises or opens when needed.
Standards and sources
- Electrical Equipment (Safety) Regulations 2016 (SI 2016/1101): regulation 3 and Schedule 1 read on legislation.gov.uk, 8 Nov 2026.
- BS 7671 (Requirements for Electrical Installations): Not read. Confirm the current edition and amendments with your electrician.
- BS 6396 (electrical systems in furniture): Not read; edition history disagrees between sources. Confirm the current edition on BSI Knowledge.
- IET Wiring Matters, autumn 2010: Electrical fixtures in furniture: read in full; dated, used for scope and direction only.
Questions we are asked
Can a table have a mains socket built in?
Yes, but it is an electrical product and an installation detail at once. Ask who supplies the module, what it is rated for, how the cable is clamped, how heat is dealt with and how it is reached for service. The electrician sets the values.
Do USB charging points in a table need a mains supply?
Yes. The module contains a power supply that runs from the mains, so ask where it sits, how warm it runs and what protects it. A USB outlet does not remove the need for the same checks.
Where should the cable run in a table?
Down a leg or panel that is not sat against, along a channel in the rail, and out of sight to the floor box, with strain relief at each entry and a slack loop where parts move. Draw it; do not leave it to the installer.
Who is responsible for a table with power in it?
The party named as manufacturer on the paperwork and the party who installs the supply each carry duties. Agree this in the contract and ask for the declaration of conformity and instructions for the finished table. This sheet is not legal advice.
Can I cut a power hole in a stone or glass top?
Only with the fabricator. Openings weaken a top and are cut before toughening or polishing, so size and edge detail must be settled on the shop drawing first.
Download the factsheet
A two-page A4 PDF with the cable-route drawing, the decision table and three specification clauses, to keep with your project file.