Electrical installations

Electricity is a very important element in a house. Lights, appliances, television, HVAC systems and security alarms all run on electricity. Electricity is distributed throughout the house by means of circuits that connect the miniature circuit breakers to the various receivers. These circuits are made up of conductors (wires), control devices such as switches and buttons, conduits (control device boxes), and connection devices such as plugs, sockets, extension sockets, lamp sockets, etc.

At various points in the circuit, there are switches that allow, for example, to turn on and off the lights in a room. A switch is an electric component that interrupts the current (or flow of electricity). It generally consists of a mechanical device set on the wall. The electricity can be transferred to the different devices by means of a socket. A socket is usually mounted on the wall and has two or three holes called female contacts. The plug is a connector composed of protruding prongs or male contacts. The plug is attached to a cable, so when you plug in an electric device, the electricity is transferred through the cable to give power to the device. Most devices have a switch to stop the power supply, so it is not necessary to unplug every time we want to turn it off.

The electric plugs and sockets might be different in other countries. The differences are related to voltage, shape and types of connectors and are the consequence of the lack of an international standard.

A house electrical plan is needed in order to do the electrical installation. There are many electrical symbols used to represent the different elements.


A building constructor hired Bill and Jordi for the electrical wiring and layout of a house under construction. The constructor handed over to them an approved electric installation plan.

Jordi: Let’s have a look at the plan. Bill, you will interpret it.

Bill: We need one circuit for lightings supplying a maximum of 10 lighting points.

Jordi: Ok.

Bill: We also need at least one circuit for each appliance such as a water heater, a washing machine, dishwasher, electric cooker, fridge, etc. rated with a 10/16 Amps each.

Jordi: Can you explain exactly what is needed in each of the rooms?

Bill: Ok. For the living room, we need a minimum of two fix lighting points, one in the middle of the room and another one next to the dining area. And five socket-outlets. There should be one at the entrance, three on the wall for the television and other gadgets, and one beside the sofa.

Jordi: What about the kitchen?

Bill: For the kitchen we need two fixed lighting points and five socket outlets: for the fridge, the washing machine, the dishwasher, the microwave, and a spare double socket for other appliances. In the bathroom we need two fix lighting points: one up, on the ceiling, and one on the wall above the mirror. And one double socket on the wall, beside the mirror for the shaver or the hair-drier. And finally, the bedroom. We need one fix lighting point on the ceiling, two socket-outlets beside the bed, and we will also need an intermediate switch to turn the light on and off from the bed and at the entrance.

Jordi: Well done, Bill! Now, with all this we will prepare a quotation and send it to the contractor.


  • Appliance: aparell (electrodomèstic)
  • HVAC systems (Heating, Ventilation and Air Conditioning): sistemes CVAC (Calefacció, Ventilació, i Aire Condicionat
  • Are made up of: estan fets de
  • Control device: dispositiu de control
  • Plug: connector
  • Socket: endoll
  • Extension socket: regleta d’endolls
  • Unplug: desendollar
  • Wiring: cablejat
  • Layout: distribució, disposició
  • Lightning point: punt de llum
  • Water heater: escalfador
  • Washing machine: rentadora
  • Dishwasher: rentaplats
  • Electric cooker: encimera
  • Socket-outlet: endoll
Taula: Some electric symbols
Símbol Significat
Lamp/light bulb. General and multifilar symbol
Lamp/light bulb. Singlewired symbol
Fluorescent. Multiwired symbol
Fluorescent. Singlewired symbol
Electric bell
Variable resistor/Rheostat (IEC)
Polarized capacitor
Magnetic Core Inductor
Iron Core Inductor
Socket outlet (power) with protective contact. Multifilar symbol
Socket outlet (power) with protective contact. Unifilar symbol
Switch contact closure or work generic symbol. Multifilar symbol
Switch opening or resting. Multiwired symbol
Switch. Normally open. Multiwired symbol
Switch, single pole. Singlewired symbol
Circuit switch. Contact cutting before making contact. Multifilar symbol
Two position switch unipolar. Multifilar symbol
Two position switch unipolar. Unifilar symbol
Changeover switch or Intermediate switch. Multifilar symbol
Changeover switch or Intermediate switch. Unifilar symbol
Push button switch. Normally open. Multifilar symbol
Push button. Singlewired symbol
Changeover switch. Multiwired symbol
Changeover switch. Singlewired symbol
Staircase relay. Multiwired symbol
Staircase relay. Singlewired symbol
Teleruptor. Multiwired symbol
Teleruptor. Singlewired symbol
Switch with built-in fuse


The present perfect is a verb tense which is used to speak about the past, but, unlike the past simple and the past continuous, the actions in the present perfect have strong connections with the present.

Apart from the basic prepositions in, on and at, there are other prepositions which are used to speak about time, as for example, for, since, before, after, etc.

Finally the passive voice (Cat. veu passiva) is a special form of the verb which is sometimes used instead of the ‘normal’ active voice (Cat. veu activa). The passive voice is more widely used in English than in Catalan and Spanish, especially in witten texts, so it is necessary to learn its forms and uses.

The present perfect simple and the present perfect continuous

The past participle is an invariable form of the verb. It is used (with the auxiliary verb have) to form the perfect tenses of the verbs and (with the auxiliary verb be) to form the passive voice.

The present perfect tenses are composed of two elements: the auxiliary verb have and the past participle form of the verb. As with the past simple, when we need to use the past participle in English we must know whetehr the verb is regular or irregular

  • In regular verbs, the past participle form adds the ending -ed to the infinitive (work > worked).
  • In irregular verbs, the past participle form is a different word from the infinitive (go > gone).

The present perfect simple

These are the forms of the present perfect simple of a regular verb (worked).

Taula: Conjugation of the present perfect simple (regular verb: work)
Long form
Short form
Long form
Short form
I have worked ‘ve worked have not worked haven’t worked Have I worked…?
You have worked ‘ve worked have not worked haven’t worked Have you worked…?
He/She/It has worked ‘s worked has not worked hasn’t worked Has he worked…?
We have worked ‘ve worked have not worked haven’t worked Have we worked…?
You have worked ‘ve worked have not worked haven’t worked Have you worked…?
They have worked ‘ve worked have not worked haven’t worked Have they worked…?

Here are the forms of the present perfect simple of an irregular verb (go).

Taula: Conjugation of the present perfect simple (irregular verb: go)
Long form
Short form
Long form
Short form
I have gone ‘ve gone have not gone haven’t gone Have I gone…?
You have gone ‘ve gone have not gone haven’t gone Have you gone…?
He/She/It has gone ‘s gone has not gone hasn’t gone Has he gone…?
We have gone ‘ve gone have not gone haven’t gone Have we gone…?
You have gone ‘ve gone have not gone haven’t gone Have you gone…?
They have gone ‘ve gone have not gone haven’t gone Have they gone…?

The present perfect simple is used:

1) To express an action that started in the past that continues in the present (usually with the prepositions for or since):

  • I have worked in this company for 20 years (Cat. Porto 20 anys treballant en aquesta empresa)
  • He has been a firefighter since 1998 (Cat. És bomber des del 1998)

In these two examples, we understand that I still work in this company and that he is is still a firefighter. If we use for or since, the actions are not finished.

2) To express a recently finished action whose consequences still continue in the present:

  • The street is wet because it has rained all night (Cat. El carrer està mullat perquè ha plogut tota la nit)
  • He is in hospital because he has had an accident at home (Cat. És a l’hospital perquè ha tingut un accident domèstic)

3) To express a finished action in an indeterminate past, usually to speak about experiences and accomplishments:

  • I have been to Canada many times (Cat. He estat al Canadà moltes vegades)
  • Have you ever worked in a foreign country? (Cat. Has treballat alguna vegada a l’estranger?)

Adverbials of time commonly used with the present perfect simple

These are some time adverbials that we often use with the present perfect simple:

  • Today (Cat. avui)
  • This week, etc. (Cat. Aquesta setmana)
  • Never (Cat. mai)
  • Just (Cat. -)
  • Already (Cat. ja)
  • Ever (in questions) (Cat. alguna vegada)
  • Yet (in questions) (Cat. ja)
  • Yet (in negatives) (encara not)

Some of these adverbs need an explanation:

1) Just has no equivalent word in Catalan or Spanish. The adverb is used to say that the action has finished very recently. In Catalan and Spanish, we express this idea with the expression: ‘acabar de’ + verb. Examples:

  • I have just met Mr Bramwell (Cat. M’acabo de trobar el Sr. Bramwell).
  • He has just gone (Cat. Acaba de marxar)

2) Yet is only used in questions and negative sentences. We usually place it at the end of the sentence. Examples:

  • Have you started the course yet? (Cat. Has començat ja el curs?)
  • We haven’t met Mr Bramwell yet (Cat. Encara no hem conegut el Sr. Bramvell)

The present perfect continuous

The present perfect continuous combines the perfect tenses and the continuous tenses. The form is composed of three elements: the auxiliary verb have + the past participle of be (been) + the gerund of the verb.

The table shows the forms of the present perfect continuous of the verb work:

Taula: Conjugation of the present perfect simple (irregular verb: go)
Long form
Short form
Long form
Short form
I have been working ‘ve been working have not been working haven’t been working Have I been working…?
You have been working ‘ve been working have not been working haven’t been working Have you been working…?
He/She/It has been working ‘s been working has not been working hasn’t been working Has he been working…?
We have been working ‘ve been working have not been working haven’t been working Have we been working…?
You have been working ‘ve been working have not been working haven’t been working Have you been working…?
They have been working ‘ve been working have not been working haven’t been working Have they been working…?

The present perfect continuous is used in the same cases as the present perfect simple, but sometimes there is a difference in the emphasis on the continuation of the action.

1) The following sentences have the same meaning:

  • I have worked in this company for 20 years.
  • I have been working in this company for 20 years. (Cat. Porto 20 anys treballant en aquesta empresa)

But we can only use the present perfect simple in:

  • I have been a firefighter since 1998.

It is wrong to say: I have been being a firefighter since 1998. Remember that there are some verbs that are not used in the continuous forms.

2) In the following sentences, the difference is in the emphasis on the duration of the action:

  • The street is wet because it has rained all night.
  • The street is wet because it has been raining all night (Cat. El carrer està mullat perquè ha estat plovent tota la nit)

In the present perfect simple, we explain what has happened to explain why the street is wet, the action is finished and it has given a certain result. In the present perfect continuous, we emphasize the duration, not the action itself. With the present perfect continuous, the idea is that it has been raining all night and it is still raining at present.

Prepositions of time (II)

Apart from the prepositions in, on and at, other common prepositions of time are the following:

1) Before (Cat. Abans de):

  • Before 1980
  • Before Christmas
  • Before going to work / Before you go to work

2) After (Cat. Després de):

  • After the meeting
  • After the holidays
  • After listening to him / After you listen to him

3) During (Cat. Durant)

  • During the week
  • During the holidays
  • During the meal

4) Until (Cat. Fins a)

  • Until 8:30 this evening
  • Until next Winter
  • Until you finish your work

5) From…to/until (Cat. Des de…fins a…)

  • From 2003 to 2006
  • From the morning until the evening
  • From May to July

6) For (Cat. Durant [tot el període])

  • For ten days
  • For more than one year
  • For one moment

7) Since (Cat. Des de)

  • Since yesterday
  • Since last week
  • Since I was younger

The prepositions of time generally go before a noun, but notice that some prepositions:

1) can go before a clause:

  • Before you leave (Cat. Abans de marxar)
  • After you meet Mr Smith (Cat. Després de conèixer el Sr Smith)
  • Until you see the new office (Cat. Fins que vegis el nou despatx)
  • Since I met you (Cat. Des de que et conec)

2) can go before a verb (always in the V-ing form):

  • Before speaking (Cat. Abans de parlar)
  • After talking to Mr Smith (Cat. Després de parlar amb el Sr. Smith)

Some differences between the prepositions of time


1) During expresses something that happened in the middle of a period of time:

  • I wrote the article during the holidays (Cat. Vaig escriure l’article durant les vacances)

2) For expresses something that happened throughout the whole period of time:

  • Yesterday I worked for 10 hours (Cat. Ahir vaig treballar durant 10 hores/Ahir vaig treballar 10 hores seguides)

For/Since (with the present perfect tense):

1) For indicates that an action has happened throught the whole period of time indicated:

  • I have lived in the country for only three weeks (Cat. Fa només tres setmanes que visc al camp).

2) Since indicates the moment in the past when the action started:

  • I have lived in the country since 4th November (Cat. Visc al camp des del 4 de novembre)

The passive voice

The passive voice is a form of the verb that we can sometimes use instead of the active voice. Catalan and Spanish, as most languages, also have a passive voice. Compare these two sentences:

  • Active sentence: Mary organized the party (Cat. Mary va organitzar la festa).
  • Passive sentence: The party was organized by Mary (Cat. La festa va ser organitzada per la Mary).

Structure of the passive sentence

Let’s see the structure of the passive sentences. Here is our example:

  • The party was organized by Mary

The basic elements are:

1) The subject: The party…: it does not do the action of the verb, as in the active sentences. In the passive sentences, the subject receives the action of the verb.

Like the past simple, the past participle of the regular verbs ends in -ed. For the irregular verbs, see the forms in a list of irregular verbs.

2) The verb: …was organized…: the verb must be in the passive form, which is composed of two elements: BE (in the appropriate verb tense) + PAST PARTICIPLE (invariable)

3) The agent: …by Mary: the agent is the person who does the action of the verb. It is introduced by the preposition by (Cat. per). It is very often omitted from the sentence.

Negative and interrogative passive sentences

To express a passive sentence in the negative or the interrogative, we must apply the same rules as for the verb ‘be’:

  • Negative: The party was not organized by Mary (Cat. La festa no va ser organitzada per la Mary)
  • Interrogative: Was the party organized by Mary? (Cat. Va ser la festa organitzada per la Mary?)

Use of the passive voice

We use the passive voice in these cases:

1) When we don’t know who did the action or when it is very obvious:

  • English is required to work in an international team (Cat. Per a treballar en un equip internacional, es requereix l’anglès)
  • The fire has not been extinguished yet (Cat. El foc encara no s’ha apagat)
  • English is spoken in many countries (Cat. L’anglès es parla a molts països)

Notice that in all these examples, Catalan and Spanish do not generally use the passive voice. Instead, they use the impersonal form of the verb: es requereix, no s’ha apagat, es parla

2) When we want to give more importance to the action than to the person who did the action:

  • The company was founded in 1986 (Cat. L’empresa es va fundar/va ser fundada l’any 1986)
  • The victim was taken to hospital (Cat. La víctima va ser portada a l’hospital)

Changing from an active sentence to a passive sentence

The change from the active voice to the passive voice will help you understand the differences between these two types of sentences. Here is an example to illustrate the changes:

Figura Changes from the active to the passive voice

Notice the following:

1) The subject in the active sentence becomes the agent in the passive sentence.
2) The direct object in the active sentence becomes the subject in the passive sentence.
3) The verb changes from the active voice to the passive voice.


  • When the subject of the active sentence has an impersonal meaning like people (Cat. la gent), someone/somebody (Cat, algú) or no one/nobody (Cat. ningú), we do not usually express the agent in the passive voice.
  • When the subject of the active sentence is a subject pronoun (I, you, he, etc.), we must express the agent with the corresponding object pronoun: by me, by you, by him, etc.

The table shows the passive voice of some common tenses of an irregular verb (do, in the 3rd person singular):

Taula: The verb tenses in the passive voice (verb: do)
Verb tense Active voice Passive voice
Present simple does is done
Present continuous is doing is being done
Past simple did was done
Past continuous was doing was being done
Present perfect has done has been done
Future will do will be done
Infinitive (to) do (to) be done

Passive sentences with two objects

Some sentences have an indirect object and a direct object. When this happens, the two objects can become the subject of the passive sentence. For example:

  • Active: Mary asked me(=indirect object) two questions(=direct object)
  • Passive: I was asked two questions by Mary
  • Passive: Two questions were asked to me by Mary


Translations and summaries are two important activities that will help you improve your reading and writing skills.

Translating a text means to express the same ideas in your own language (direct translation) or from your own language into another language (indirect translation). Nowadays, there are many automatic translators that can be very useful to understand a text in English, but if you must submit your translation to other people, it will be necessary to make some corrections because an automatic translator will inevitably generate lexical and syntactical mistakes.

On the other hand, summarizing a text means to express the same ideas, but in fewer and usually different words. Summaries will help you improve your reading skills because you will learn to distinguish the most important ideas of a text.


When we learn a foreign language (Cat. llengua estrangera), we translate from one language to the other all the time. For example, when we read in English, we mentally translate the language into our mother tongue (Cat. llengua materna) in order to understand the text. When we write in English, first we think in our mother tongue and then we mentally translate it into English. Similarly, when we speak English, we think in Catalan or Spanish and then we translate our thoughts into English. This is the normal process when you learn English outside an English speaking context. However, as you advance in the study of the language, you must ‘learn’ to think in English. This means that your thoughts will come naturally in the foreign language.

You should be aware that nowadays many professional documents, like manuals and correspondence, are written in English. As some people do not speak English yet, you should learn how to make a good translation so that other people can understand a text in English. Apart from this practical reason, translating a text will also help you understand the foreign language better and practise your reading and writing skills.

To make a translation, you can use the following tools:

  • A bilingual dictionary (paper or online).
  • An automatic translator.

The most important thing in a translation is to transmit the same idea of the original language as well as possible, but using the most common structures of the language into which you are translating the text. However, sometimes it is inevitable to lose some information when translating from a language into another.

Bilingual dictionaries

Paper dictionaries are little used nowadays. However, it may be useful to have a pocket dictionary at home or at work for looking up (Cat. consultar) the meaning of unknown words. Online dictionaries are more widely used because they offer many advantages. For example, with an online dictionary it is quicker to find a word (you don’t have to turn the pages), it is constantly updated, you can access to lots of extra information, you can always carry it with you in your mobile devices and very often you can also listen to the pronunciation of the word. You can find hundreds of free dictionaries in the web.

See the ‘Interesting links’ section for a list of online dictionaries.

Here are some instructions to use a dictionary appropriately (paper or online):

  • If the word is inflected, look for the base form (although many online dictionaries include inflected forms). For example, do not look for the meaning of did, look for do; do no look for easier, look for easy.
  • Do not take the first meaning of the word that you find. Very often, a word has several meanings. You must consider the context and choose the meaning that has more sense in that context. For example, we cannot translate the verb work in the same way in: The computer doesn’t work (Cat. L’ordinador no funciona) as in: He doesn’t work on Mondays (Cat. No treballa els dilluns).
  • Consider the part of speech (it’s a verb, a noun, an adjective?). Sometimes they have the same form, but the meanings are different. For example, the word working is not the same in a working day (adj.) (Cat. un dia laborable) as in I’m working (v.) (Cat. Estic treballant).

Automatic translators

Automatic translators are very much used nowadays for translating words, sentences and whole texts. They are very useful for understanding the meaning of an email in English or a short text from a manual, for example. Automatic translators are more and more accurate everyday. However, a text generated by an automatic translator is usually full of syntactical and lexical mistakes. For this reason, it is necessary to read the resulting text carefully and correct the mistakes, especially if the translation is destined to other people.

Here is a translation of a technical text from English into Catalan. Compare both texts and notice the different syntactical structures:


English version

As with many computer-related devices, mice are being combined with other gadgets and technologies to create improved and multipurpose devices. Examples include multi-media mice, combination mice/remote controls, gaming mice, biometric mice, tilting wheel mice and motion-based mice.

(from the website www.howstuffworks.com)

Translation into Catalan:

Com és el cas en molts aparells informàtics, els ratolins es combinen amb altres aparells i tecnologies per tal de crear dispositius millorats i polivalents. Alguns exemples són els ratolins multimèdia, la combinació de ratolins i comandaments a distància, els ratolins utilitzats en els jocs, els ratolins biomètrics, els ratolins amb la roda inclinada i els ratolins basats en el moviment.

The process is the same in the case of what is generally called a ‘reversed translation’, that is, a translation from the mother tongue into a foreign language. When we write in English, we usually make a reversed translation because we tend to think in our own language and then translate our thoughts into English.

The use of automatic translators for writing in English is not recomended for several reasons:

  • The text that you introduce must be very well written and have absolutely no mistakes. If you miss a comma, a graphical accent or mispell a word, the text will be full of mistakes. For example, the translator may interpret the words anglès and angles differently.
  • An automatic translator does not generally distinguish the context or the language style required, so we must make sure that it translates exactly what we mean.
  • If the objective of writing is practising your skills, you will miss the effort that you need to make for learning because the translator will do all the work for you.


Writing a summary means to express the most important ideas of a text in a few words. A summary often means to change the words and sentences of the original text, but sometimes you can simply cut down the text by eliminating all the superfluous information and keep only the main ideas. From the point of view of learning, writing a summary is an excellent means of practising your writing and reading skills.

To write a summary, you must follow these instructions:

  • Include only the main ideas.
  • Do not include superfluous information. This includes: examples, words and sentences to reinforce the main point, repetitions of the main idea to give emphasis, etc.
  • Try to use more simple sentences and your own words as much as possible. Where it says: I was astonished to hear that you had resigned your post you could say, for example: I was surprised to know about your resignation.
  • Do not change the information of the original text. You must say the same, but in fewer sentences.
  • Do not express your own opinion in a summary or add information that is not in the original text.

Writing a summary requires some practice and some knowledge of the basic vocabulary and syntactical structures of the language, in this case, of the English language. Here are some tips for writing a good summary:

  • First of all, read the whole text to have a general idea of the contents.
  • Write down what you remember of the text without looking at it.
  • Read the text again and underline or highlight the main ideas: see if they coincide with the ideas that you have written down.
  • Write down the summary carefully. When possible, choose more simple sentences; you can also use the same sentences, but make sure that you eliminate all the unnecessary information.
  • Read your summary. If you think that it is still too long, cut out all the unnecessary details or try to change the sentences for more simple ones. A summary should be as short as possible without losing any important information.

Here is an example of a summary:



The Island

In recent years, we have seen significant developments in cloning. Sheep, cows, cats and, more recently, dogs that have been cloned in the name of scientific progress. One of the potential use of cloning is to ‘grow’ replacement organs for people who are ill in human clones. It is this subject that is portrayed in a new film released this week in the USA called ‘The Island’.

The film features Ewan McGregor and Scarlett Johanssen and it raises awareness of this highly controversial moral issue. However, in spite of excellent performances from both main actors and spectacular special effects, the film received a disappointing reaction from American audiences. It is possible that the subject is too difficult and that some audiences prefer thrillers without the moral dilemmas. The film opens in the UK next week and it will be interesting to see how the British audiences react.


The Island

The new film ‘The Island’, which deals with the controversial subject of cloning people, has not been received well in the USA. Although the acting and effects are very good, some audiences may have been disappointed by the moral message of the film.

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