Cyclic and Emergency Cable Ratings to IEC 60853

A cable sized on continuous full load is often larger than the circuit needs, because generation and storage circuits rarely run flat out. IEC 60853 rates the cable against the load shape it will really see, and separately against the overload it has to survive for a defined period. The first can save a conductor size. The second is what tells you whether an N-1 condition is survivable.

When You Need It

  • · The circuit has a distinct daily shape, which is normal for solar and for storage
  • · You want to know whether a smaller conductor is defensible before committing to the larger one
  • · An emergency or N-1 condition puts a cable above its continuous rating and you need to know for how long that is acceptable
  • · A client or DNO has questioned a rating based on a load factor

Standards Applied

IEC 60853IEC 60287

The report states the clause and the edition it works to, so the calculation can be reproduced by whoever reviews it.

What You Get

Cyclic rating for the stated daily load shape, with the shape itself recorded in the report
Emergency rating for the stated duration, with the conductor temperature reached
The comparison against the steady state rating, so the benefit being claimed is visible
A clear statement of the preceding load condition assumed, because an emergency rating is meaningless without it

Small firms rarely offer this, and it is often where a conductor size is won or an N-1 argument is settled. It sits on top of the IEC 60287 model, so it is quick once the steady state case exists.

Frequently Asked Questions

What load shape do you use if we do not have one?

We will propose one appropriate to the technology and state it plainly in the report, so anyone reviewing it can see exactly what was assumed and challenge it if they disagree.

Can a cyclic rating be used for the DNO submission?

Often yes, but it depends on the operator and on how firmly the load shape can be relied on. We will tell you where the argument is strong and where it is not.

Request a Cable Sizing Study

A free calculator answers one question at standard conditions. A study takes the actual route, burial depth, soil resistivity, grouping and load profile, and gives you a signed report you can issue to the DNO or the client. We take single calculations as readily as full cable system designs.

Or call 07951 651 013 or email enquiries@stardeltapower.co.uk