When You Need It
- · Single core cables are being used at 33 kV and above, which is most substation and export circuits
- · A route is long enough that single point bonding may not hold the standing voltage within the limit
- · A DNO has asked for the standing voltage to be demonstrated
- · Cable losses matter to the energy yield and the bonding arrangement has not been examined
Standards Applied
The report states the clause and the edition it works to, so the calculation can be reproduced by whoever reviews it.
What You Get
The standing voltage limit in GB practice is commonly 65 V under normal load, per ENA ER C55, but operators and clients do specify lower. We confirm the figure that applies to your connection rather than assuming it.
Frequently Asked Questions
Is the free calculator enough for a design?
It answers a single circuit under balanced load, which is the right first check. A design has to deal with the real section lengths and joint bay positions, parallel circuits inducing into each other, earth fault conditions, and the energy duty on any sheath voltage limiters. Those are not calculator work.
Single point or cross bonding?
Single point is simpler and cheaper and works until the section gets long. Cross bonding cancels the voltage across three minor sections and lets the route run further, at the cost of link boxes and the discipline to get the transposition right. The section length calculation tells you which one you are in.
The Rest of the Cable Chain
Review, calculation, drawings, testing and fault location, from one place. See the whole picture.