The Civils a Substation Is Actually Built From
A substation compound is a civil engineering job with electrical equipment standing on it. Levels, foundations, drainage, containment, access and security all have to be designed, and they all have to agree with the electrical layout that sits on top of them.
We design the civil package, with the structural calculations behind it, in the same programme as the electrical work rather than after it. That matters because the two keep colliding: duct sizes and depths are set by the electrical design and carried by the civil drawing, and when different firms hold each half the gap between them turns into site queries.
A substation also does not energise because the electrical design is finished. It energises when the DNO is satisfied, and the items that hold that up are rarely electrical. Foul provision, a water supply, a duct route crossing somebody else’s land: these turn up late, carry long lead times, and sit outside most electrical scopes.
What We Design
Any of it on its own, or the compound as one package.
Substation and compound design
The whole compound: platform levels and earthworks, hardstanding, access roads and turning heads, crane and delivery routes, fencing and gates. The civil package a substation is actually built from.
Foundations and structures
Transformer plinths and bunds, switchgear and gantry bases, support structures, control and relay building foundations, retaining structures where the levels demand them. With the structural calculations behind them.
Drainage and containment
Surface water drainage and attenuation, oil interception and bunding, cable trenches, troughs, ducts and chambers. Sized for the equipment and the ground, not copied from a standard detail.
Water and foul
Mains water connection and the undertaker application, foul provision where there is no connection to take it, and alternative supply such as rainwater harvesting to BS EN 16941 where mains is not available or not yet available.
Duct routes and trenching
Duct routes to DNO and Openreach specification: cover depths, duct type and bore, marker tape, chamber and joint box details, road crossings and building entries.
To the DNO’s own standards
Where the connection is to a DNO, the compound has to satisfy their civil standards as well as the electrical ones. NGED SD2A/1 is the one we work to most, and it carries requirements that are easy to miss at design freeze.
What You Receive
- General arrangement and setting-out drawings, issued for comment, for construction and as-built, in PDF and DWG
- Civil and structural design calculations
- Levels and earthworks: platform design, cut and fill, and the drainage that falls out of it
- Foundation and plinth design for the equipment actually being installed, not a generic detail
- Equipment and materials specification, with sizing where it is a sizing problem
- Siting and layout worked from the topographic survey and the ground investigation
- Trial-pit sections for every crossed service
- One review round per deliverable
Drawings are issued in the language the owner’s engineer expects, because they are written to survive that review rather than to be redrawn after it.
Common Questions
Why buy substation civils from an electrical consultancy?
Because the two keep colliding. Duct sizes, depths and separations are set by the electrical design, and the civil drawing has to carry them. When one firm sizes the duct and another draws the trench, the gap between the two is where the site queries come from. Here the same consultancy does both.
What does NGED SD2A/1 actually require?
Among other things, a cesspool rather than a septic tank for a 132 kV substation, and provision for an alternative water supply where mains water is not available. Both are easy to miss at design freeze and expensive to add afterwards, because they affect the layout and the access route.
Can you do the water undertaker application as well?
Yes. The design and the application go together, and the quotes water undertakers issue have a validity window, so the sequencing matters more than people expect.
Is this available without the electrical design?
Yes. It is a service in its own right, and plenty of it is bought standalone by a developer or an EPC who already has an electrical designer.
How much of the compound can you take on?
All of it. Platform levels and earthworks, foundations and plinths, drainage and bunding, cable containment, access roads and hardstanding, fencing and security, and the buildings. Equally, one element on its own is a job: a transformer plinth, or a drainage design, or a duct route, without the rest.
Do the structural calculations come with it?
Yes. A foundation drawing without the calculation behind it is not a design, and an owner’s engineer will ask for both.
Tell Us About The Site
The site layout, the topographic survey and what the DNO has asked for is enough to come back with a scope and a fee.