Choosing the Right Extension Cord and Wirings

Many a time,  we use an extension cord to extend our power supply for connection to a laptop,  Hifi Audio,  Television, and many other appliances.  They are cheap & easily available.  Sometimes,  we use such extension cords for slightly heavy current appliances such as electric irons & kettles.   

Most extension cords we buy off the shelves are not suitable for very heavy current appliances,  not because the plugs and sockets cannot take the load but because the flexible cable used is too small for carrying such higher electric currents.  A quick test one could do is to turn on the appliance for about a minute,  we should feel that these underrated cables will start to warm up.   The better extension cord will always have the ratings specified on the extension cord but the cheaper ones might not. 

This article will try to give some information on how to choose the extension cords and how to size up the flexible cable if one decides to DIY an extension cord.

Extension Cords

There are generally 3 types.  The common ones are sold as switch socket outlets.   They are either in single,  double, or multiple gangs as shown in the top left-hand picture. The other common ones in cable reels where the cables can be reel in and out for storage purposes as shown in the top-right-hand picture.  For those requiring heavy-duty for industrial applications,  they are shown in the lower pictures. 

What to look for?

When buying an extension cord,  it is important to know what we will be using the extension cord for and how long will be the cable or rather how far the appliance will be located away from the wall power sockets. We will be looking at the load-carrying capacity of the extension cord and the loading distance of the extension cord.

a)  Load-Carrying Capacity

For example,  if we are using the extension cord for television,  HiFi audio set,  laptop, or Christmas lights, most extension cords will be able to do the job.   But if we use the cord for electric irons and kettles which will drain higher current,  we will need to be careful and pay some attention to selecting the correct type of extension cord;  otherwise,   the cable might not be big enough to "carry" the electric current or the load.  As a result,  the cable might be heated up over long hours of operation. The wiring insulation could melt causing electrical short-circuiting,  giving rise to fire incidents.

The better ones and branded ones will usually have a rating specified on the extension cords.  Most of them will have a rating capable to handle a maximum load of 13 A or 3,000 watts.  That would mean it could be used for an electric iron or a kettle which usually consumes about 4 to 5 amperes or 1,000 watts.

b)  Loading Distance

The household extension cords usually come in fixed-length of around 2, 3, or 5 meters;  some, 3 meters long;  extension cords the heavy-duty or the industrial type can be of lengths 20 meters or more.  Users do not usually have to worry about the cable ratings of extension cords so long as one is using the extension cords within the manufacturer's maximum specification.

Extension Cord Ratings & Safety Labels

Various countries have different statutory requirements or safety codes for the use and application of extension cords.   Most regulatory authorities will want the extension cords to comply with the local manufacturing safety standards.  Nonetheless, it is always wise for users to choose a brand that has a safety label sticker over those which neither give any ratings or brands or operating ratings.

What about DIY?

DIY is not any cheaper than those available off the shelves but if one needs a specific length of cable,   the only way is to design and self construct the extension cord.

What to look for?

The things to look at are about the same as the commercial extension cord except one will have to size up the cable.   One would need to size up the cable to handle not only the carrying load but also to account for the voltage drop caused by the cable.  

Take, for example,  a cable of a certain size that might work fine when the cable is short but might not even be enough to run the same appliance when the chosen cable is about 30 meters long. This is because the voltage at the receiving end might have dropped to below the acceptable limit for the proper running of the appliance.

How to size up the cable?

There are 3 common and different sizes of flexible cable one can easily buy off the shelves;  these are specified in the following manner under the imperial system:   23/0076 & 40/0076 & 70/0076 as follows.

The Technical specification of the flexible cable under the imperial system is as shown in the following.  There is also one for the metric system.

  

Column 3 of the table indicates the maximum ampere that the cable can carry and volume 4 and 5 indicates that voltage drops for the cable to carry the maximum ampere. For household application which is usually 1 phase ,  we will be looking at column 4 to size up the cable. 

Let's assume we have an electric iron consuming about 1 kW @ 220 Volts,   that is roughly 1000/220 or 4.5 amperes. The above table says 23/0076 can take up to 6 amperes which might be able to carry the load.  But in turn of voltage drop,  it will have 4.5/6*11 or 8.25 volts over 100 ft or 30 meters,  this is about 8.25/220 or 3.75% which is higher than 2.5% specified under the regulation, Therefore,  this cable is not suitable under such usage.

The next cable size (40/0076) will have 4.5/13*14/220 or 2.2% voltage drop.  It might just make it but the one size larger (70/0076) would be more suitable for prolonged hours of usage.

Testing

It is always good to ensure that the correct size of the cable has been selected for the operation by also measuring the temperature of the cable when it is under operation.   The cable temperature should not exceed 70^oC.   One should also ensure the cable is always installed according to the acceptable color code which is green/yellow for earth, blue for neutral, and brown color for the line or live cable.  

Replacing 2x40 Watts Fluorescent Fitting with LED Downlights

We have a situation where 2 Nos of 40W 4 feet fluorescent fitting were fitted inside a lightbox having an egg crate lighting diffuser at a ceiling height of about 3.5 meters.   We wanted to change them into LED lightings not only to save energy but also to get a brighter lighting system for the sitting room.   We came across these cheap 5 watts downlights which we have retrofitted with good results.  This article will describe how we retrofitted them and how we improved the lighting system with cheap materials found in the house.

The Downlights

These downlights are not only cheap, but they are also quite bright if one only could carefully read the reviews that some of the buyers were saying.  We replaced the 2 Nos of 40Watts fluorescent fitting with 8 Nos of these little glitters and managed to get a better and brighter lighting level.

How?

As advertised & to our surprise,  we found the brightness of this little glitter is equivalent to about a 60-80W incandescent lightbulb.  As downlights are direct lightings, their lighting output will not be cut by the egg crate diffusers which we had had in our old lighting setup using 2x40 Watts fluorescent fittings. 

Retrofitting

The retrofitting was relatively easier with the egg crate diffuser.  All one needs is a wire cutter that one can use to cut a hole of about 60 cm in diameter. Wiring up was a piece of cake with the quick wiring connector that one can wire up the lamps in a matter of half an hour with simple double core wirings.  Each lamp consumes only about 5 Watts so any type of double core wiring would be suitable.

Calculated Energy Saving

If what was claimed is to be true that each LED downlight consumes only 5 Watts,  the total wattage saved for replacing the 2x40Watts fluorescent fitting will be around 60 Watts considering that a 40 Watts fluorescent fitting will consume 50 watts including the ballast which will consume another 10 watts.   The total saving would be roughly  60 W x365 days x5 hrs per day or about 109 kWh per year.  At an electricity cost of around $0.25 per kWh,  the saving  would be around $27/= per year.  This is about twice the cost of the downlights which is around $1.60 each.

Shortcomings

The only shortcoming we have had is the glare from these fittings.  It is quite unbearable especially when it is installed at such a height.  It is quite eye-catching and disturbing when one sits on the couch,  looking at them.  There were no lampshades we could find online to fit the lamp.  Finally,  we use cupcake plastic bowls we found sitting at the corner of the house.  This is how we did it

Things to watch out

1)  Buying the downlights

There are many varieties of downlights available online. Most of the cheaper ones are from China. They all use the same advertising pictures and descriptions and appeared to be the same but actually,  they are from different manufacturers;  therefore,  they can be entirely different.    When they claimed to be white light in color,  some might be a mixture of bluish and yellowish light.  The lighting level can also differ.  It is good to read the review to buy the correct type.

2)  Cutting the holes in Egg Crate Diffuser

The plastic could be old and brittle after some years of working.   Be careful when cutting the hole.   Plan first before deciding where to cut the hole.  It would not be possible to repair the hole after the hole cutting.   Hot glue is good assistance if some piece of the egg craft came loose while cutting the hole.    It is a good practice to glue a round plastic ring to reinforce the rims of the egg crate cuttings.

3)  Safety First

Go without saying.  Make sure the power is always off before doing any electrical work and advise that no one will turn on the power while one is working on any electrical wiring work.

 

Austria is Locking Down Again

Austria announced last Friday that they are locking down.  This is the fourth national lockdown.   The lockdown will begin on 24 November;  it is likely to last for the next 10 to 20 days. 

This lockdown shall make  Austria the second European country, after Latvia, to impose lockdown measures since vaccines became widely available earlier this year.  Further,  Austria is contemplating making vaccination compulsory.  

What's the use of Lockdown?

Lockdown is an effective but primitive way to curb the spreading of all types of diseases. Lockdown has been used for centuries whenever there is an epidemic.  The idea is to isolate the patients especially those asymptomatic ones so that they won't have a chance to roam around, spreading the diseases to other healthy people in the Community.  This article will show that asymptomatic patients are responsible for more than 60% of the Covid transmission.    

Lockdown is good,  but it comes with a price.  Many people especially those in Western Countries so hated lockdown that they often went to the streets protesting against such practices.   

Mass testing will also have the same effect of "isolating" those asymptomatic after "flushing" them out from the community.   ART is a good alternative to mass PCR testings.   Proper use and handling of ART is not only cheaper but also more cost-effective. 

The Situation Right Now in Austria

It is not looking good.   The infection cases shot up about 3 times from 586 per million on Oct 12 to about 1562 per million on Nov 22 for slightly more than 40 days.  It is sad to see that the death rate has also doubled in that period.  However, it was not as serious as before and after 2/3 of the residents have been vaccinated.

What could have happened?

A new Covid wave has been formed except this time,  Austria is better prepared as shown by the following charts.

The charts show clearly that Austria has done plenty of testing.  The rate is around 77 tests per 1000 people. This rate is about 4 times more than the UK's 13.5 and 15 times more than Singapore's 3.2.  However,  the positive rate of the test is not high @ 2.8%.   The exceptional high testing rate in Austria explains why its infection rate has gone up so fast and so sharp.   The charts also show that Singapore's positive rate is exceptionally high @ about 17% which is about 4 times that of the UK's  4.6%. 

Why Singapore has such a high Positive Rate?

Normally,  any Epedilogist will say countries having a high Positive Rate is not a good thing.  It means the infection is very serious;  there must be a lot more other infection cases still roaming in the streets.  The infection wave is not over.   More new cases are expected.   However,  this is not the case in Singapore.   Singapore has just seen its new cases drop by 2/3 over one month. This is as shown in the following chart which is plotted in the daily-infection interval.   The new cases dropped from 976 per million on 27 October to 326 per million on 23 November.   

Why so?

It has something to do with the mandatory Antigen Rapid Testing (ART) that Singapore has just implemented in September 2021,  and the detail of which is explained here.  Singapore managed to find 5 times more or about 3,000 to 4,000 asymptomatic patients per day using ART and isolate them quickly to prevent them from spreading Covid in the community.  

As the Singapore Authority is replacing the screening PCR testings,  they cut down the PCR testing frequency,  resulting in higher positive rates as illustrated in this chart

In Singapore's case,  the higher positive rates are not caused by the seriousness of the infection.   

Of late,  the experts in Singapore are questioning the needs of the electronic system that traces Singaporeans' outdoor movement for reasons to track the contacts of infectious patients.   

How Austria can Get such a high Testing rate but a low positive rate?

This might have something to do with the free and uniquely PCR Self-Test method introduced by Austria in September 2021.

https://www.afr.com/policy/health-and-education/why-citizens-in-pandemic-vienna-keep-gargling-20210922-p58tzr

In such an exercise,  everyone in Vienna will be given a PCR test (gargle box) free.  They can pick up the box at any of the 22 BIPA outlets.  After doing the test,  the box is handed over to the REWE outlets or the petrol stations.  Users can get the test result within 24 hours. 

The exercise could have gathered lots of  PCR testing samples.  Because 2 tests are required to confirm infection cases and they have to go through each and every one of those samples,  the positive rate would naturally be lower.

Because of the very high testing rate and high infection cases which primarily are assumed to be asymptomatic patients,  Austria should see the crisis over in a very short time.

Can Other Countries do the same as Singapore?

There should not be any reason why other countries cannot do and repeat the same;  after all, the ART testing method started in Europe and the US.   All they have to do is to make ART testing kits easily accessible to residents.   People are curious by nature and afraid to die.  They will want to know what's wrong with them.  They will use the testing kits one way or another.

As for Singapore,  it should not rest on its laurels.   It should continue to make improvements,  making ART test kits freely available and accessible to all Singaporeans,  residents, and even the short-term travelers at no or little cost over 24/7 outlets using ATM machines located all over the island.  After all,  asymptomatic are the ones that contributed most of the infection cases because of the sheer numbers.  The government could save the cost through savings in the reduced numbers of PCR testings.

 

Estimating the Transmission Risk of Asymptomatic in a Community

It is generally known that symptomatic patient has a higher transmission risk.  According to this article by Yale Medicine,  a Delta symptomatic patient can spread to maybe 3.5 or 4 other people.  As for asymptomatic patients,  the common knowledge is that its transmission risk is relatively low. This article will try to examine from a different approach why some were saying that asymptomatic or people without symptoms are responsible for about 59% of the Covid transmission.

What happens at the site?

Ministry of Health (MOH) of Singapore has this pie chart showing that about 98.7% of the patients are asymptomatic or patients with mild symptoms.   This has been the case for many months.  It is quite clear that there are lots of asymptomatic/patients with mild symptoms in the community.  

How are they Responsible for the Transmission?

One can always argue that asymptomatic is not responsible for the spreading of Covid in the community.    It is always the symptomatic patients passing on the Covid to the asymptomatic.

According to this study which examined and traced the contact histories of about 7,000 people,  asymptomatic patients have a transmission rate of 0.06% whereas symptomatic patients have a rate of 1.12%

In other words,  let's say we have 10,000 people in a community,  9,800 people are asymptomatic and 200 people are symptomatic or pre-symptomatic as found out according to the MOH Singapore,  we might have this situation:   

Therefore,  there is a possibility that the asymptomatic can be 75%  responsible for the spreading of Covid in the community.

Other Studies

There are also other studies that have similar findings;  for example,  this study from Oxford Academy found that the secondary attack rates of symptomatic and asymptomatic were 4.1% (128 of 3136) and 1.1% (12 of 1078), respectively.  This Oxford study indicates that asymptomatic can have an even higher transmission risk,  causing or contributing more infections in the community. 

Conclusion

This simple example confirms this article saying that asymptomatic or people without symptoms are responsible for about 59% of the Covid transmission.  Therefore,  we mustn't underestimate the importance of asymptomatic patients who are usually hiding in the community.   These patients will always stay and spread Covid in the community until there is a mass-testing done to flush them out.  In the case of Singapore,   instead of using mass testings,  they introduced in September 2021 the mandatory Antigen Rapid Testings (ART) for the workers and residents.  This has helped to flush out about 4 to 5 times the number of these asymptomatic patients hiding in the community.

The Unvaccinated Are Not Happy Today

They are not happy because they are thinking the Governments,  almost all over the World are trying to fix them.  They are:

1.  Beginning to "open up" allowing only the vaccinated to travel;

2.  Implementing unfair practices to restrict their movements such as visiting the public places,  PUBs  and eatery shops;

3.  Forcing them to be vaccinated;  last but not lest;

4.  Talking about them responsible for spreading the Covid.

They demanded to know why people always blame them.

Why?

To understand why we must be prepared to know why the governments all over the world are doing so much to stop the spread of Covid.   Why aren't they worked up about the spread of the Common flu?    They have only one thing in mind, which is to "save their Health Service from collapsing".

They are not worried at the beginning when only a few were sick and eventually died although they had tried their best to save them.   They analyzed the data and found that there were more unvaccinated getting sick and the vaccinated are having either no symptoms or mild symptoms.   They also found that there are more unvaccinated than vaccinated getting infected.  As people with symptoms are having a higher chance to spread Covid,  they started to blame the unvaccinated.

When the majority are vaccinated,  the situation changed,  more and more vaccinated are getting sick.  Of late,  even the rate of vaccinated is getting infected,  at times having higher rates in hospitalisation than the unvaccinated.   They began to understand the effectiveness of the vaccine had started to wane.  They introduced booster shots.  At the same time,  the fewer unvaccinated leftover is getting even more skillful and careful.  They prevented themselves always from getting infected.

However,  one thing has never changed.  There are more unvaccinated getting severely sick and dying eventually.  This has unfortunately loaded up the Government's Health Services.  They tried to fix this.  This MOH Singapore chart tried to show that the unvaccinated have 9.4 times and 22.5 times the chance of getting severely sick and dying respectively.

They changed their tone now to say they are protecting the unvaccinated.

https://www.moh.gov.sg/news-highlights/details/protecting-the-vulnerable-securing-our-future

Why VTL?

Rightly speaking,  there is no real good reason to ban those fewer unvaccinated who can take extra precautions to have the chance to travel.  The Governments must be thinking that although these unvaccinated can take such extra precaution back home,  they might not be able to do so when traveling abroad.   It is likely that unvaccinated will have a hard time trying to convince their Governments that they are equally capable of preventing themselves from contracting Covid while traveling overseas.  And until the unvaccinated can do so,  the "decree" is likely to remain.

New Measures Poping up

Because the unvaccinated are more prone and vulnerable to being severely sick,  there will be calls everywhere from the vaccinated,  demanding the unvaccinated to pay for the medical bills if they get infected.

The unvaccinated will definitely be very unhappy,  but in countries like Singapore where the unvaccinated are the minority,  their voices would not be loud.    The country will start charging Covid patients who are ‘unvaccinated by choice’ by 8 December

Conclusion

The unvaccinated have every reason to be unhappy about the present restrictions imposed on them especially they can show data and statistics that vaccinated are equally vulnerable to infection and hospitalisation.   However,  one thing they cannot change is the higher rate of unvaccinated getting severely sick and then dying.  This is the only reason and they now saying "they are protecting the unvaccinated"

Why should Elderly be Vaccinated?

Governments all over the World are trying to pass on the message that the elderly,  older than 60 years of age are vulnerable to infection.  Many of those deaths are in the 80+ age group.    They tried to post all sorts of charts and figures,  supporting their claims;  however,  many elderly are still not serious. Why?.

How Vulnerable are these Elderly?

Yahoo has an interesting graphical table showing the death rate of various age groups in a week from July 11 to September 4.  This table must have been constructed using data from US CDC.  

Source:  https://news.yahoo.com/age-still-huge-coronavirus-risk-090059106.html

Explanation

The table shows, for example,  54  among 100,000  unvaccinated people above 80 will die each week.  On the other hand,  10 of 100,000 vaccinated people in this will also die each week if they are not careful.

What is the Difference from Other "Stories" Being Told?

There is no difference.  This "Story" is still too complicated for most of the elderly.     Not many elderly will understand especially when many have only gone to elementary schools when they were young. These people are more sensitive to numbers than rates,   which is a mathematical term.    After all,  they are the ones deciding if they should get vaccinated.

Why Elderly in Singapore not Excited?

Many a time,  we read about forumers in the discussion groups always asking why Singapore Government does not publish death numbers by vaccination status.  This is despite Singapore Government has made an effort to publish and compare the % of people dying by vaccination status on a daily basis.

Unfortunately,  this MOH's chart is not showing the numbers for the elderly.  It is showing the rate for vaccination and unvaccinated across all age groups.  The figure of 5.4 per 100,000 for the unvaccinated is 10 times smaller than the 54 per 100,000 for those 80+ as reported by Yahoo.

Then What are the numbers?

According to MOH of Singapore,  the following is the position of vaccination among the various age groups.

https://www.moh.gov.sg/covid-19/vaccination

The chart clearly shows that about 12% of those >80 are unvaccinated.  6% of those 70-79 and 5% of those 60-69 are unvaccinated

About 770 or 1.5% of those elderly above 60 in Singapore who are unvaccinated are expected to die each year. Those aged above 80 and unvaccinated has the highest death rate  @ about 300 or 3% per year.  The breakdown figures for Singapore is as shown in this table.

Estimated Death Numbers for Unvaccinated of Age Above 60 @ 7 Nov 2021 for Singapore
	Age Group			Total	Remarks
Age Group	60-69	70-79	>80
Population number (I)	500,124	244,727	96,228		Data source: https://data.gov.sg/dataset/resident-population-by-ethnicity-gender-and-age-group?view_id=2f273a73-de27-4242-a602-8165789f96d3&resource_id=d5d35678-cd15-4f43-b347-d671d1870655
% Unvaccinated in Group (II)	5%	6%	12%		Data Source: https://www.moh.gov.sg/covid-19/vaccination
Unvaccinated Nos(Estd) III=(I*II)	25,006	14,684	11,547	51,237
Death per 100K per week(IV) (Yahoo expressed in %)	13.08	35.96	54.39		https://news.yahoo.com/age-still-huge-coronavirus-risk-090059106.html
Death per week (Estd) (III*IV)	3	5	6	15
Death per year (Estd) (III*IV)	170	275	327	771
% of Unvaccinated	0.68%	1.87%	2.83%	1.51%

One could work out a similar table for other countries using the same method.  As the death rate might differ from country to country,  the working should only be taken as a reference.

Update:  17 November 2021

MOH has just published this new chart reporting on the death rate of vaccinated and unvaccinated for those between 60 – 69, and above 70 years old.   This chart shows that the death rate of unvaccinated is about 12 to 14 times higher than vaccinated for these 2 elderly age groups.

If we compare Singapore's rate to the USA's rate,  we can get this table:

Average Weekly Death Rate (Numbers per 100,000
Age Group	USA	Singapore	USA	Singapore
	Unvaccinated		Vaccinated
80+	54	13	11	1.1
65-79	36	3	2	0.2
55-64	13		1
USA: for period between July 11-Sept 4
Singapore: for period between Oct 9 to Nov 16
Note: some discrepancy expected as Singapore's figure is for 60-69 and >70 instead of 65-70 and >80

No wonder the Singapore Authority recently claimed Singapore was having one of the lowest death rates in the World.  

The comparison table might not be fair to the US considering that Singapore is a city-state and a small country and US is a big country with many different demographics,