science

IEC 60038

IEC 60038 is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand IEC 60038 rather than just read about it. In short: International Standard IEC 60038, IEC standard voltages, defines a set of standard nominal electricity supply voltages for low voltage and high voltage AC and DC systems. Tables The standard primarily contains a set of tables, each of which define a set of standard nominal supply voltages that may be chosen from, as follows: Table 1 defines those for AC systems where voltage is to be within the range 100 to 1000.

Key takeaways

IEC 60038 belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect IEC 60038 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of IEC 60038 from memory before moving on to harder problems.

Reference excerpt

International Standard IEC 60038, IEC standard voltages, defines a set of standard nominal electricity supply voltages for low voltage and high voltage AC and DC systems.

Tables The standard primarily contains a set of tables, each of which define a set of standard nominal supply voltages that may be chosen from, as follows:

Table 1 defines those for AC systems where voltage is to be within the range 100 to 1000. Table 2 defines those for DC and AC traction systems, and provides DC options from 400 to 3600, and AC options from 4750 to 27500. Table 3 defines those for three-phase AC systems where voltage is to be within the range 1kV to 35kV. Table 4 defines those for three-phase AC systems where voltage is to be within the range 35kV to 230kV. Table 5 defines those for three-phase AC systems where voltage is to exceed 230kV, and gives options up to 1200kV. Table 6 defines nominal voltages for equipment below 120 V AC, or 750 V DC.

Low voltage systems (Table 1) Standard nominal voltages that can be used for low voltage systems in the 100-1000V range are as follows:

For three-phase 3 or 4-wire systems at 50 Hz: 230 V (3-wire) 230/400 V 400/690 V 1000 V (3-wire) For three-phase 3 or 4-wire systems at 60 Hz: 120/208 V 240 V (3-wire) 230/400 V 277/480 V 480 V (3-wire) 347/600 V 600 V (3-wire) For single-phase 3-wire systems at 60 Hz (American split-phase): 120/240 V Note that with the exception of the American split-phase case, where two voltages are given separated by a slash, these represent 4-wire cases; the first voltage corresponding to that between phase and neutral, and the second between phases. Single voltage values are for 3-wire cases and thus correspond to that between phases. In the case of American split-phase, the first value is that between a hot and the centre-tapped neutral, while the second is that between the pair of hots. All AC voltages are RMS. Three-phase 3-wire is without neutral, while three-phase 4-wire is with neutral. Of historical interest, it is noted that the 230/400 V three-phase option replaced the former 220/380 V and 240/415 V systems. Similarly the 380/660 V system was replaced with 400/690 V. Migration from these older voltage systems was required by amendment 1 to the 1983 edition of the standard, published in 1994. Those countries with a 220/380 V systems were required to bring their voltage within +6/-10% of 230/400 V, while those with a 240/415 V system were required to bring their voltage within +10/-6% of 230/400 V, as soon as possible, and no later than the year 2003, thus achieving all systems being within ±10% of 230/400 V by that deadline.

Worked examples

Example 1 — a first encounter with IEC 60038

Start with the simplest possible case. Write down what IEC 60038 claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to IEC 60038 before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about IEC 60038 ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of IEC 60038

In research: IEC 60038 appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses IEC 60038 in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: IEC 60038 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Electric power distribution, Electrical wiring, IEC standards, so understanding it makes those chapters shorter.
In everyday life: Look for IEC 60038 outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study IEC 60038 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what IEC 60038 means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain IEC 60038 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is IEC 60038 in simple terms?

International Standard IEC 60038, IEC standard voltages, defines a set of standard nominal electricity supply voltages for low voltage and high voltage AC and DC systems. Tables The standard primarily contains a set of tables, each of which define a set of standard nominal supply voltages that may…

Why does IEC 60038 matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study IEC 60038?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on IEC 60038.