Generator power?

[CGW]

What is the best (safest!) way to supply power to the house from a generator?

I have a 10kw generator, currently I am using a "heavy duty" extension to connect to the generator then back feeding into the house, extension cord has a 20a circuit breaker built in, this is getting hot when trying to run all I won't, which I would guess amounts to ~4kw.

Thanks

[Crossy]

It is imperative that you cannot connect the generator and mains supply at the same time.

 

There are many simple and cheap manual transfer switches available online, spend a bit more and you can go full auto start. 

 

What make and model is your genset? Single-phase / 3-phase?

 

EDIT Here are a few threads to get you started.

 

https://www.thaivisa.com/forum/topic/1038638-too-many-village-blackouts-need-advice/

 

https://www.thaivisa.com/forum/topic/983260-jupiter-generator/

 

https://www.thaivisa.com/forum/topic/1008069-connecting-a-portable-generator-advice/

 

[CGW]

Noted on the mains connection, got that covered.

Gen is Honda 6500 https://www.honda.co.za/en/products/power-products/generators/eg6500cxs/model-overview/specifications/

Thanks.

[Crossy]

OK so she's a 6kVA single-phase beastie, electric start but not full-auto ready.

 

6kVA @ 220V is about 27A so you'll need at least 2.5mm² (preferably 4mm² if you run near full load) cable from the genset.

 

The blue 32A "Commando" plugs and sockets are readily available and what you need if you are not going to wire everything permanently. These:-

 

 

You may find this thread useful, read it to the end. Even if you don't go full-auto the automatic stop when the power comes back is most handy.

 

 

 

 

[CGW]

Thanks, that helps, I have 2.5 cable, there is a "special" plug that goes into the generator, a plug to backfeed is a problem, looked before could find nothing, the above plugs obviously wont plug straight into the mains, is there an online source for plugs etc? I looked everywhere I knew in Udon and found nothing rated as high as needed.

Is it ok to go direct from Gen to backfeed with no breaker in between?

[Crossy]

How are you interlocking your generator and mains feeds? It is extremely unwise to rely on "remembering" to unplug something before turning on breakers. 

 

Interlocked switches are not expensive.

 

The genset should have a breaker on its output to protect it, no real need for another breaker.

 

[CGW]

25 minutes ago, Crossy said:

How are you interlocking your generator and mains feeds? It is extremely unwise to rely on "remembering" to unplug something before turning on breakers. 

 

Interlocked switches are not expensive.

 

The genset should have a breaker on its output to protect it, no real need for another breaker.

I agree it is unwise to have to "remember" but that is what I am doing! I have written down a basic procedure to follow, but its only as good as the person who follows it! thats why I want an alternative, not familiar with interlocked switches? will look it up,

I had an "Electrical" friend initially hook it up when he was visiting but we couldn't find the components he needed on the local market so ended up far from perfect!

[Crossy]

Have a look in the threads I linked to earlier, there are a few examples of simple (cheap) interlocked switches.

 

For less than $10 this is good value https://www.aliexpress.com/item/2P-63A-MTS-Dual-power-Manual-transfer-switch-Circuit-breaker-MCB-50HZ-60HZ-400/32786129292.html

 

[CGW]

Thanks, I will have to think about this overnight, currently thinking I lack the knowledge & confidence to fit one of these, as still not clear to me!

[Crossy]

35 minutes ago, CGW said:

Thanks, I will have to think about this overnight, currently thinking I lack the knowledge & confidence to fit one of these, as still not clear to me!

Just to be clear.

 

What you have now is potentially lethal to either yourself, your family or the poor souls who are trying to re-connect your power. I hope your personal liability insurance is up to date.

 

Oh, and it could place your generator in low earth orbit.

 

[CGW]

16 hours ago, Crossy said:

Just to be clear.

What you have now is potentially lethal to either yourself, your family or the poor souls who are trying to re-connect your power. I hope your personal liability insurance is up to date.

Oh, and it could place your generator in low earth orbit.

No pressure to get it right first time then, thats good, I generally learn from my mistakes! ?

 

 

[Wirejerker]

I hope no one is using a lead with a plug on each end (suicide lead) to connect their genset. Your wall mounted plug should look similar to this.
https://www.lazada.co.th/products/pce-16a-230v-3pin-2pe-i7515343-s9383748.html
And connected through a correctly wired change over switch


Sent from my iPad using Tapatalk

[CGW]

32 minutes ago, Wirejerker said:

I hope no one is using a lead with a plug on each end (suicide lead) to connect their genset. 
https://www.lazada.co.th/products/pce-16a-230v-3pin-2pe-i7515343-s9383748.html
And connected through a correctly wired change over switch

Unfortunately I am! 

Bear with me, I am only undertaking this as there is no one else! would gladly pay to have someone competent install.

I now understand what is needed and where to get the parts for connecting genset to change over switch, I know where to get a changeover switch, but still not grasping the wiring or placement for the change over, where will this be connected to on the mains breaker, obviously not the main breaker switch as would be backfeeding?

[Jdietz]

Main house feed -> This new transfer switch -> House Main Circuit Breaker

Generator -> Other input of this new transfer switch

 

The transfer switch is special in that it is mechanically impossible for the two circuit breakers you see in the picture to be on at the same time.

You have to turn one off first.

 

Mind you you will work on a live mains when switching over. Don't do this yourself. Have an electrician stand with his bare feet on a 7-11 plastic bag instead. (yes he did..)

 

[Crossy]

3 minutes ago, Jdietz said:

Main house feed -> This new transfer switch -> House Main Circuit Breaker

Generator -> Other input of this new transfer switch

Yes, if he uses this particular transfer switch, and his board supports DIN mount devices, it can replace the incoming breaker as it's actually two 2-pole MCBs (the one shown is 63A other sizes are available).

 

If our OP can post some images of his incoming supply arrangement (with the covers off) we can provide more directed assistance.

 

However, I do not recommend he does this himself, he states that he's not competent. If we point in the right direction he can get a local sparks to do the dangerous stuff.

[bankruatsteve]

22 minutes ago, CGW said:

Unfortunately I am! 

Bear with me, I am only undertaking this as there is no one else! would gladly pay to have someone competent install.

I now understand what is needed and where to get the parts for connecting genset to change over switch, I know where to get a changeover switch, but still not grasping the wiring or placement for the change over, where will this be connected to on the mains breaker, obviously not the main breaker switch as would be backfeeding?

Crossy's post a few back showing a transfer switch also shows the wiring for that.  There are two "in" - 1) mains  2) from a cable that goes to your genset.  There is one "out" - that will go to the mains input in your CU.  Just to make things simple, you want the transfer switch as close to your CU as possible.  If you have a knife blade (or other) mains isolator before your CU, that makes a DIY a bit easier.  In any case, you will need to disconnect where the mains currently enter your CU (main breaker) and re-connect to the transfer switch for mains in. .  That's it for the simple set-up.  Automatic start is a bit more challenging.

 

If you don't have an isolator switch before your CU, then you really need to find someone to do it for you.  IE: The isolator can cut power before the CU which will let you safely change over to the transfer switch.  Without that your mains Live will be Live and not a job for the inexperienced.

[CGW]

32 minutes ago, Crossy said:

 

If our OP can post some images of his incoming supply arrangement (with the covers off) we can provide more directed assistance.

 

However, I do not recommend he does this himself, he states that he's not competent. If we point in the right direction he can get a local sparks to do the dangerous stuff.

This is the breaker I want to connect to, I am a retired Engineer, I worked a lifetime around high voltage equipment, which gave me a very healthy respect for electricity! if it's not clear to me what is needed I want be attempting it, if only there was a competent "local sparkie" last time I used him had to redo what he did!

 

[Crossy]

OK, that's great.

 

Do you have any test gear? A cheap multimeter and a neon screwdriver are very useful and low cost.

 

Some observations.

• Please check the polarity of your incoming supply, it seems that the grey is live and the black neutral, this is the opposite way round to the Thai standard.
• Your incoming breaker is 100A. Check your meter, is it a 30/100 or 15/45?
• If you have a 30/100 then you'll need a 100A transfer switch, I'll have a hunt for a suitable unit.
• You also have no earth-leakage protection, I suggest you install an RCD (Safe-T-Cut in local language) as soon as possible, we can combine with the transfer switch.
• You'll need a second box anyway.

 

[bankruatsteve]

So, those big wires going into the bottom of the main breaker are the ones you would want to move to "Mains In" on the transfer switch.  The problem with that is that it appears they are coming direct from your meter so the re-connection would have to be done with LIVE wires (unless there is disconnect at the meter).  The other problem is whether there is enough cable length for re-route to the switch AND getting a live wire out of the metal box without shorting something out.  This really needs a disconnect somewhere so that it can be done safely. Anyway... the output from the transfer switch would then replace the mains in the main breaker.  Yah?

[Crossy]

A thought.

 

What you could do is determine which of those circuits you want to run off the generator and move them to a separate smaller box with the transfer switch in it. Then you could feed that from one of the breakers in the current box.

 

No need for live working then as it's all on the switched side of your incoming breaker. Also, you wouldn't need to use a 100A transfer switch (anything over 63A adds $$$).

 

You'll still need someone to install a Safe-T-Cut mind.

 

[Crossy]

23 minutes ago, bankruatsteve said:

The other problem is whether there is enough cable length for re-route to the switch AND getting a live wire out of the metal box without shorting something out.

This is why I like plastic consumer units (despite the fact they are no longer permitted in the UK). I can pull live wires around in (relative) safety, no risk from hitting an earthed metal box.

[bankruatsteve]

Looking at that box photo again.  I see only 4 neutral wires attached to the neutral bar but with 12 live.  Hmmm.  

 

I wonder if that would confound a separate circuits box?

[Crossy]

5 minutes ago, bankruatsteve said:

Looking at that box photo again.  I see only 4 neutral wires attached to the neutral bar but with 12 live.  Hmmm.  

Nah, those are (should be) the grounds (green ground sticker to the right of the bar). In a Schneider box the neutral bar is to the left of the incomer (with all the black wires on it).

 

I wonder where that fat black wire on the ground bar goes, hopefully to a nice ground rod.

[CGW]

33 minutes ago, Crossy said:

OK, that's great.

 

Do you have any test gear? A cheap multimeter and a neon screwdriver are very useful and low cost.

 

Some observations.

• Please check the polarity of your incoming supply, it seems that the grey is live and the black neutral, this is the opposite way round to the Thai standard.
• Your incoming breaker is 100A. Check your meter, is it a 30/100 or 15/45?
• If you have a 30/100 then you'll need a 100A transfer switch, I'll have a hunt for a suitable unit.
• You also have no earth-leakage protection, I suggest you install an RCD (Safe-T-Cut in local language) as soon as possible, we can combine with the transfer switch.
• You'll need a second box anyway.

 

Have a Multi meter, yes the grey is live.

Meter - don't know! see picture, this isn't the only JB for the house, there are three, two I know have independent supply, no way to isolate power that I can see.

 

I'm starting to feel "electrically inadequate"! 

 

 

[CGW]

1 minute ago, Crossy said:

I wonder where that fat black wire on the ground bar goes, hopefully to a nice ground rod.

I Can guarantee it does! that I did check..

[Crossy]

8 minutes ago, CGW said:

I'm starting to feel "electrically inadequate"! 

I think you are far more "adequate" than you admit ?

 

Meter is a 30/100 (look to the left of the barcode, above the word "Mitsubishi"). Thanks for posting decent hi-res photos, you would be amazed at the junk images we have to look at ?

 

Ok, so long as we know that grey is live we're good.

[Crossy]

Is this your house or a rental?

 

If a rental then minimal cost should be expended, if it's yours then spending a bit more for a better job would be wise.

 

[CGW]

Not rental, cost not an issue (within reason!) 

[Crossy]

I would look for a point on the incoming supply before it splits off to the other boards and install a 100A isolator there, you can then disconnect the lot at a single point.

 

The "Chang" brand knife switches are cheap and effective and far safer than they look, but do try to put it out of reach and out of the rain. You can get your local sparkie to do this then send him on his way whilst you do the rest properly, you need the 100A version.

 

 

 

Do all of your "essential" circuits come from one board?

[CGW]

3 minutes ago, Crossy said:

I would look for a point on the incoming supply before it splits off to the other boards and install a 100A isolator there, you can then disconnect the lot at a single point.

 

The "Chang" brand knife switches are cheap and effective and far safer than they look, but do try to put it out of reach and out of the rain. You can get your local sparkie to do this then send him on his way whilst you do the rest properly.

 

Do all of your "essential" circuits come from one board?

The only point I can think off where you could tap into the incoming supply would be at the meter as the cable run is underground into the house, I was onsite when it was run.

 

All the "essentials" that I could run from Genset are on this board, the other main breaker is bigger, then there is one outside for pumps, workshop etc, will have to dig some old pictures out to see how it was run.