Recently, uncle bought one cheap surge protector powerstrip from MR DIY store at RM24 something?

But, to uncle dismay, the MOV is installed at wrong place. As the result, only one socket is protected from possible surge while the other three are not.

Some pictures below (large image):



Searching around the net for the MOV model returned:

https://www.sunrom.com/p/10d471k-varistor-mov-for-220v-ac


Data from https://www.sunrom.com/get/559199 seem to indicate:

Aside from the wrong MOV placement in the powerstrip, the MOV itself is fine for its intended purpose.
How in the world this thing qualify as surge protector when it only protect one socket out of four sockets?

SIRIM tengah tidur ke?

Parking

Abang engineet bole tau bape gaji abang?

wat is mov

SIRIM bayar only. No need test also pass.

wow got sirim sticker

From eyeballing the innards seems like the singlr mov protects all sockets (when individual sockets switched on). Look at the common N and L rails.

Then again I'm not an electronic circuitry expert.

The MOV is being installed across Line and Neutral which is correct. Since this is a single phase socket array, all the 3 (Line Neutral and Ground) are shorted together via the copper busbar. Therefore the potential differences between the sockets should be negligible.

More expensive surge arrestors will have MOV across line-line, line-neutral, neutral-ground and line-ground. Obviously this Mr DIY is just a extra precaution instead of full protection~ better than nothing i suppose haha

movie file format

Sirim keje diamond lekat sticker saja

for sensitive item, get AVR please.

Mr DIY items are cheap because they don't last. I usually buy them for emergencies. They do stock branded ones but quite expensive.

Wah, who pass the sirim cert??

Kena liao.

mr diy start selling branded items already, you can see philips and pentene there.
also hotak sets is good enough for my usage too. their single piece of screw driver oso good as well.

erm..................

ts bodo

Yes, I know about those three lines protection.

In MR DIY powerstrip, if there is power surge and all four switches are turned on, only Green socket will be protected from surge while the Blue, Orange and Red sockets will be hit by surge.

In this case, the MOV should be installed as shown below in red line (Point of entry):

This way, all four sockets will be protected from surge coming from Live wire by redirecting surge to Neutral wire out.
I have no idea why the MOV is installed that way protecting only one socket and still pass SIRIM.

U get what u paid la

Wadeyer expect from rm24 item, furthermore its mr diy

Report to SIRIM!

wanna beter protection, better buy Cal Lab

ayam buruh nelayan dan juga petani

apa MOV MOV ni? ELI5 takda ka?

Look carefully. It's the same.

Uncle must have failed electronics in college. The MOV is placed in the COMMON ground and neutral point - which is exactly the same as what you mentioned in the later post.

Dude, English please ELI5

Except electricity doesn't work that way. It will always travel along the path of least resistance. What the MOV does is to give it an easy alternative so the MOV burns up instead of your load. So essentially electricity doesn't really care whether it is 'nearer' or 'further' UNLESS there is added impedance which I don't believe to be the case because your power switch is barely 1' long...

Try taking a multimeter and measure the resistance between your proposed location and the actual location. Probably u get less than 50ohms. When the surge comes in at 1,000 volt, it probably isn't going to care about the 50ohms haha.

lol. TS oh TS

Now that is something new......
If that the case, why do those high end surge protector MOVs normally located before the socket or load?

Even the protection voltage also wrong.
Should be 275

Anyway, when 1000V comes along, do you think that small MOV will help?

Industrial surge protection cost thousands of dollars. And most of all, they have good grounding (which also cost thousands to achieve).

RM24 expect belkin RM90

Well the truth about surge protection is electrical surges are kinda unpredictable in terms of amplitude (peak to peak volt) or duration (surge time) so designing a perfect surge arrestor is close to impossible. Even industrial surge protector guys such as Emerson etc usually do not offer any sort of guarantee.

In fact some manufacturers put multiple MOVs across the same system in hopes that one of them 'catches' the strike. Theoretically installing a MOV at the 'entrance' is a good industry practice but there is no concrete proof that installing elsewhere along the PCC (Point of common coupling) affects the efficiency of the surge arrestor system.

If you have an expensive equipment, investing in a proper surge arrestor instead of Mr DIY is highly recommended

pls dont tell me u r an electrical engineer

we get single phase 220, 240v is rms value. peak is 220 X root(2).

275V hancur lor

What do u expect? A few hundred ringgit quality when u just buy it for few bucks? Simple terms. U get what u pay for.

you can say its electrical energy in Joule. its one of the specs.

it can many-many volts.

it depends on how much electrical energy absorbed in Joule

it will work

but not a good design

lel these cheapo thing got surge protector? jew so gullible to believe them?

betul la use 471

if that MOV is not imitation, it can offer surge protection across Live n Neutral as per spec.

There is nothing wrong with the varistor placing. It did connect to live common and neutral common.

If you said it just protect the green, than the varistor should connect to the copper plate after the green switch.

so i bought expensif belkin wan for over hundred rm ok o not?

It’s the same, they are all connected at the same line.
I doubt the parasitic inductance has any effect on it.

This post has been edited by Drian: Aug 13 2018, 08:42 PM

I just read what those manufacturers product training brochure mentioned about MOV placement......it recommends the MOV to be installed at 'entrance' of power input.

Wouldn't installing MOV at 'entrance' mean that location is path of least resistance once the varistor start to conduct after encountering a surge?




I am not.


But seriously, I am not planning to use it for 1000v or lightning strike protection, just day to day small surge from high powered motors/heaters (Neighbours car cleaning/washing business)

Mr DIY surge arrestor also can spark discussion LOL

u wrote 275... the 275 is part number or volt?

where did i write?

in anycase if got one behind the part number, usually is multiplier la.

still selling aaa..? last time bought one from them way back then. seller like cheebai but product is good

wow.. i learned something new and useful in /k

what a rarity

it's a crappy dump site for china products. some are ok but a lot of crap sold there

OK

i saw the data sheet. it can be used.

the question here is can 275V damage ur load? if can, then hv to go 275V

sorry
u did wrote 275 lol

This post has been edited by endau02: Aug 13 2018, 08:47 PM

want safety, want quality dont cheapskate, simple as that

Using back your diagram,



If the impedance between the 2 points are negligible, then these 2 points are at the same electrical potential. I guess manufacturers don't know this value that's why they recommend putting at the 'entrance'? And Mr DIY probably installed it at whichever cheapest location

u got eye sight problem?

come i screen cap for you who wrote 275

Must read fine print. How many sockets are protected.

Hmm, make sense.

So, sifu ....Is it fine if I move current MOV location to entrance just to be safe? Or I just leave it as it is?
Since I don't even know the impedance between those two points and MR DIY probably installed it randomly.

ok sorry

*okay.jpg*

alrite its all good.

I not sifu la lol. If you paranoid then make a trip to Jln Pasar, buy another MOV with same part number and stick it to the entrance also can.

What makes u consider surge arrestors at the first place? If your lights dim while your neighbours wash their car it's better to check grounding instead

Aside from dimming, the light also become brighter suddenly for few seconds.

I can feel my table fan rotation suddenly speeds up a lot before returning to normal speed after my neighbours shut down their equipments.

stick
LN
LE
NE

Planning to do so.
It appears electrical shop nearby my housing area got sell this kind of stuff. Hope there are higher joule rating available for sale.

This.

don't buy one of those flashlights that charge via plugging straight into the wall.
fire and shock hazard.

Add "pls don't electrocute yourself in the process" disclaimer here.

Ministry of Virgin
Metal Oxide Varistor

Mr DIY shop tumbuh mcm cendawan.
In my area got 2-3. I never visit one.
Selling mediocre quality stuff?

cheapo but for the price is good
dont expect big brand quality la

Repot sirim ..i dont want my 10k laptop burn ..

if you own a 10k laptop, you should use cal-lab product + industrial grade AVR and original charger.

in malaysia, our official voltage is
230V single phase, variation -6% +10%
meaning from 216 to 253

most appliance can withstand +/- 10% of 230, meaning 207 to 253

thus the need of mov at 275V

if you use a 400V mov... slightly higher voltage (non lightning) will burn your everything connected. equivalent to dont install.

btw, you must have a fuse to disconnect the MOV once it got hit by lightning. else will bbq your house.

Trust me, I am an engineer.

It should be ok.

Then again, I have been wrong before.

/k really have lots of expertise.. hmmmm... 😄

ayam guna belkin power surge only mia still strong after 7years
diy kaput

This post has been edited by cikalakacikaci: Aug 14 2018, 12:58 AM

How many victims in yoUr wrong?

Metal Oxide Varistor

No one died yet, to the best of my knowledge.

Sirim sticker is not guarantee a product (as a whole) is safe for use. For example, 3-core extension wire, roll type. The sticker is on the 3-pin plug receptacle and it is for certify the receptacle only. The body, wire and other components are not covered by the sticker. But when people buy it they thought the whole thing is certified safe.

but good discussion

Haha why buy mr diy surge protector? Go get belkin ke something like that.

still using this for 7 years for my pc with high load usage

the rest use cheapo socket

Thanks for info, uncle

Park dulu, masuk opis baru study...

You oay money they stick lah. Just like halal logo.

Anyway, i cannot brain why people buy cheap eletrical product from Mr Diy and actually expect high quality protection?

This post has been edited by MarioKart: Aug 14 2018, 09:01 AM

lol uncle, look carefully la. you can say that it only protects green socket if one of the terminals is placed at the metal part below the green switch. at current state, the MOV terminals are between incoming live and neutral, exactly as they should be.

Some diy stuff are not worth to buy...

It's from Mr DIY. So, if you think it is placed wrong, DIY it.

Anyway the thinny-tiny MOV wont help with a real surge...

This post has been edited by IamNOT: Aug 14 2018, 08:14 AM

Nothing 's wrong for SIRIM to approve this product. It meets the spec on what it is intended for.

Varistor is small power and protect the basic L and N line. Probably cost no more than RM5. So, I consider the power strip is not worth that RM24

stuff is cheap china mari.. what you expect?

Not a big fond of this surge regulator stuff on almost every damn power strips in the market. I connect power amp for audio on power strip. Depending on audio, current draw can go extremely high in a short time.

Speaking of SIRIM, the real certified Surge Protector/Extension cords get a sticker on the plug and on the extension body?

if u xsuka, then buka tered and diy yoself the mov

it connected to the main line so entire socket is protected la , if u say the MOV connect after the switch yes it is only protect one socket


This post has been edited by bereev: Aug 14 2018, 08:39 AM

sirim kata ok jer

stop making accusation if i am the socket manufacturer i can send LOD to u, the 3 line straight connect to all socket the MOV put every where also same effect if it is connected after the switch then this MOV are only protect the particular socket , but this photo clearly show the MOV connected to the main line before the switch.

u try plug in and power on but dun switch on any of the socket use test pen to test the place of MOV connect it is live , means the MOV are protect the whole gang of socket. It is just place at the end of the main line

This post has been edited by bereev: Aug 14 2018, 08:46 AM

Prepare to get sued by Mr DIY lol