Hooking back-up generator to main electric panel

[likethemthin]

Hello:

I am trying to wire in a generator into my main electric panel. I have 220 volt single phase service, and although I was supposed to have 100 amp service, the main circuit breaker in my Schneider panel is 63 amps, and never trips.

I attempted (with an electrician) to get Two “safety cut circuit breakers” one for 63 amps, and one for 50 amps for my generator which outputs 32 amps.

The idea was to have two identical switches leading in to the Main panel (by installing the 63 amp safety-cut circuit breaker ahead of the main panel (i.e. attached directly to the incoming main electric and then to the main panel. Of course the other safety-cut circuit breaker would lead the generator power to the main panel, with of course only one being “on” at one time.

This was to solve the problem of not being able to source any manual transfer switches either here or abroad.

What occurred after set-up was that the safety-cut circuit breaker placed between the mains and the electric panel kept tripping immediately. Electrician said I needed a 100 amp safety cut circuit breaker, but I am not so sure any such item can be connected directly to the mains.

My questions:

1. Can one of those “safety-cut circuit breakers” even 100 amp if available which I doubt, be connected directly to mains power? I am thinking the answer is No because not sure they are designed for that. But not sure.

2. Would it be better to create a “master electric panel”, in other words a new main electric panel which would only have two circuit breakers, a 63 amp like I have now and a 50 amp for my generator; and then place this panel ahead of my main current panel, which would essentially become a sub-panel. (Of course only one of the two new circuit breakers on at a time). Does this sound like a workable idea?? In other words, I already have 63 amp breaker, so another 63 amp breaker ahead of it would be OK?

Many thanks for any guidance or input.

Walter

[Lamkyong]

i am going to follow this thread with interest by the way do you have suitable fire fighting at hand

[lopburi3]

1. 63 amp is the normal breaker size for 15 amp meter service.

2. Single Safe-t-cut at same 63 amp should work if there is not a ground fault in your home. Turn off panel breakers (Safe-t-cut should not trip) and then turn on one at a time to locate the bad circuit and then try to find/correct the fault.

Will leave second question as you really should have a transfer switch and can not believe they are not available here. But yes you can have breakers ahead of other breakers or RCCD's

[likethemthin]

Many thanks lopburi3. Actually My meter is 30 (100) amp. I looked at the front. I am way out in rural Loei.

My original electrician knew I had all this electrical appliances (he grounded each A/C separate), and yet when the dust settled, I ended up with my main circuit breaker being 63A.

Originally when the Provincial electric Authority came out for inspection prior to final meter connection, they said I had a problem in that I should have had 100Amp Circuit breaker and there was a discussion about them ordering for me since I could not source locally. But after a week or so, they came without warning and just installed the 30 (100) meter. And so I still have 63A service but never trips...probably because not enough power here anyway.

There are no transfer switches period in Thailand. I tried to source in US but could not find anything for a 220 volt system, and some sellers said the transfer switch (looks like an electric panel with two circuit breakers one for main, one for generator input plus interlock to avoid both on) would not work because circuit breakers are rated for 240/120 there which apparently means not for 220).

That's why I mentioned making my own transfer switch (which won't have any interlock device!!!) by creating a new “master electric panel”, in other words a new main electric panel which would only have two circuit breakers, a 63 amp like I have now and a 50 amp for my generator; and then place this panel ahead of my main current panel, which would essentially become a sub-panel. (Of course only one of the two new circuit breakers on at a time).

Seems you feel that could work.

Thanks again.

[Bantex]

I wired up a 6KVA electrical generator to my house years ago using a switch similar to this

Which is housed in a heavy duty plastic box.

My switch reads 1, 2, & 0.

Mains power is connected to the house on 1.

Generator is connected when turned to 2.

When switched to "0" no power supply is connected. Ideal when carrying out further work.

Only one feed can be connected at any time and nothing additional was added as the original breakers are fed from both supplies.

The generator can be hard wired directly into the circuit or by using a male/female connector, the generator can be connected only when needed.

[Crossy]

Whatever you do it is imperative that the generator and mains supply cannot possibly be connected at the same time! This is non-negotiable. Only turning one breaker on at once does NOT meet this requirement unless there is a physical interlock preventing both breakers being on at once.

What you are proposing is potentially lethal. Either to your generator (if the mains is on) or to the poor PEA tech who is working to restore your power (if the mains is off)!!!

There are a number of generator transfer switches available, both automatic or manual, or you could build your own. Have a look at this thread (read to the end) http://www.thaivisa.com/forum/topic/671221-build-a-low-cost-semi-automatic-generator-transfer-switch/

Something like this is a quick and easy solution http://www.aliexpress.com/item/2P-63A-230V-MCB-type-Dual-Power-Automatic-transfer-switch-ATS/32308090228.html?spm=2114.01010208.3.56.KlVzJH&ws_ab_test=searchweb201556_9,searchweb201602_3_10017_10005_10006_10034_10021_507_10022_10009_10020_10008_10018_10019,searchweb201603_1&btsid=1b028355-2111-4ca2-9826-fa2ce3e021a4 you could replace the genset side breaker if you wish.

[lopburi3]

As said above make sure you have an interlocking system to prevent both systems going to home or to each other. It can be a really simple manual transfer switch - you just switch source.

The 63 amp breaker is fine on larger meter - just do not want to go the other way around. 63 amp and 15 meter is what most of us have and I used 9,000 baht of electric last month and have never had main breaker blow (5 air conditioners - 5 refrigerators - water cooler - pump - 5 electric showers and 9 people so a rather heavy user.

You do need to find out why the Safe-t-cut is tripping - it is not because of its size. Is there a bypass mode (not 5-10-30 or whatever) and does that allow electric to flow? Expect it will and you have some leakage from something (could be one of those grounded a/c units and not notice). But only way to check is return to normal mode and remove everything until trip stops and then add one breaker at a time - and when breaker found one item on that breaker at a time. Although might not be serious danger this could be a matter of life and death so you should make it a priority. You already have the Safe-t-cut so you should make use of it.

[keeniau96]

Per Crossy re the aliexpress link. The link is listed as "2P ..." but the specs further on say " 220V (2P),380V (3P or 4P) ". I gather that it would be suitable for my 3-phase Phuket electric service. Yes?

[Crossy]

Per Crossy re the aliexpress link. The link is listed as "2P ..." but the specs further on say " 220V (2P),380V (3P or 4P) ". I gather that it would be suitable for my 3-phase Phuket electric service. Yes?

Several sellers do a 3-phase version one example here http://www.aliexpress.com/item/4P-63A-380V-MCB-type-Dual-Power-Automatic-transfer-switch-ATS/1895148154.html?spm=2114.01010208.3.1.jBySZy&ws_ab_test=searchweb201556_10,searchweb201602_4_10017_10005_10006_10034_10021_507_10022_10009_10020_10008_10018_10019,searchweb201603_9&btsid=0c723b9d-f0cd-4c95-9a53-8a89c9254f18

IMPORTANT If you have a 3-phase supply it is essential that you use a 3-phase transfer switch, even if you have only a single-phase generator and use one phase for 'essentials'. Also the terminals marked as N MUST be used for the neutral (they open last and close first).

[The Brit]

If you go to either of the two link below you should have a chance of overcoming your problem.

http://www.electricaltechnology.org/2013/11/how-to-connect-portable-generator-to-home-supply.html

http://www.theiet.org/forums/forum/messageview.cfm?catid=205&threadid=64200

good luck.

[Crossy]

http://www.electricaltechnology.org/2013/11/how-to-connect-portable-generator-to-home-supply.html

I worry about this link as all the examples bar one have no interlocking to prevent both supplies being connected at once!!

His "Please be careful" warning cannot substitute for a proper change-over switch.

[likethemthin]

Hello Again:

Lot of great advice!! Thanks. My Safety Cut was tripping because electrician did something wrong adding a switch to my Franklin well pump. Wow, I sure wish I had found that nice blue changeover switch. I found the other one pictured, but only in US and cost of shipping was beyond. Even though it is a Schneider changeover switch (double throw transfer switch) Schneider Thailand was oblivious....I could not source it. ABB has a LOT of changeover switches on their website, but again , after several inquiries both phone and email by a Thai friend, never got anywhere. They want to know which one you want but no help to learn which one you need.

So I settled on essentially building my own manual transfer switch with two 63 amp circuit breakers in a "new" master panel ahead of the existing electric panel, in which the Mains enter one breaker, and the generator lines enter the other, side by side, and both outputting to the existing panel input which is also a 63A main breaker.

I know about the danger, so will have my sheet metal guy create an interlock plate that slides back and forth and prevents both breakers in my "new" panel from being on at same time. In other words, only one power will be servicing my existing panel, either the mains or the generator.

The reason I wanted the generator to serve whole panel is to be able to select one or two circuits at any one time, maybe cooker in morning, Air Con in evening, just depending on what time of day utility power is off.

But if anyone thinks I will blow myself up with this kind of manual transfer switch, please tell me now!!!! Thai electrician seems to think this is OK, but not totally confident he knows more than me and I do not know much.

Thanks again for helpful comments.

Walter

[Crossy]

I've seen people make simple mechanical interlocks before. Some work better than others but at least they act as a reminder that you must not have both breakers on at once (you can of course have both OFF at once).

I would not recommend someone doing this, there are enough reasonably priced 'proper' units about, but since you already have it ...

Ours is fully automatic and wife-proof, half the time she doesn't even notice the genset has been running (can't hear it over the telly which is on a UPS).

EDIT One of these may fit in the panel you've made. Foolproof and inexpensive. Note it is purely a switch, no over-current protection. http://www.ebay.co.uk/itm/125-amp-changeover-switch-240V-mains-to-generator-transfer-single-phase-Din-rail-/272117440663?hash=item3f5b76a097:g:CLAAAOSwx-9W1FUn

[likethemthin]

Wow Crossy, that is Exactly what I have been looking for a long long time!!!! I will go buy it immediately. I just bought my other stuff and can return no problem.

One last question, I looked at the back, it does not seem to be compatible with either the Schneider or other panel boxes I saw at Home Pro (our only supplier). Can you tell what panel box it might work with? do I need a panel box at all? I will go back to that Sellers website and try to investigate if you don't know off hand. Great item, perfect, and even has every terminal marked!!!

Many many thanks, you are a scholar and a gentleman!!

Walter

[Crossy]

You need a DIN rail box, the ABB System proM series will do the job, bags of room inside for a customisation job, get them from HomePro and the like.

If you just want to house that transfer switch this should do the trick https://www.directtoshop.com/product/188344

I spotted that switch a while back and haven't seen the like even on aliExpress, origin is China, no idea why I can't find it elsewhere.

[keeniau96]

Thx Crossy, that 3-phase auto transfer switch at aliexpress looks like just the ticket. I have had good success with about ten orders at aliEx and will order that switch this week. Now to get a small generator for backup power to live through the all-too-frequent power shutoffs in Phuket. Really just need it for the master BR aircon and the and the computer UPS (two of those) so might just make a small panel for those two lines and the transfer switch.

[likethemthin]

Actually, I see where it does sort of hook on the back, and fill fit a Home Pro panel box Haco brand.

[likethemthin]

Should have not been so excited, and purchased instead the one that already comes with a box!!

[Crossy]

Should have not been so excited, and purchased instead the one that already comes with a box!!

I don't see the one with a box, got a link?

[IMHO]

Should have not been so excited, and purchased instead the one that already comes with a box!!

I don't see the one with a box, got a link?

It's fromthe same vendor:

http://www.ebay.com/itm/125-amp-changeover-switch-240V-mains-to-generator-transfer-with-metalic-box-/162045848130?hash=item25baaf6a42:g:tsYAAOSwKfVXGPfA

I bought the no box version - the extra shipping on the box version (+7 GBP) alone is enough to buy a box locally

Thanks for the heads up on this one Crossy, I've been looking for a reasonably priced transfer switch for a couple of years now, hehe.

[likethemthin]

Hello: The Link for the changeover switch in a weatherproof box is here on the A-1 Electronics ebay site:

http://www.ebay.co.uk/itm/changeover-switch-125a-240-V-mains-generator-Weatherproof-enclosure-IP65-125-amp-/262262389729

and actually, I even see the blue switch for changing between two sources that the other poster kindly pictured above at the same site:

http://stores.ebay.co.uk/A1-Electrics?_trksid=p2047675.l2563

it seems Crossy has uncovered a treasure trove of great generator parts!!!

Walter

[likethemthin]

I see from IMHO, that there are two boxes for this unit available, one a metal enclosure, and one a plastic weatherproof one.

[likethemthin]

But as Crossy said: The ABB box from Home Pro just as good: "You need a DIN rail box, the ABB System proM series will do the job, bags of room inside for a customisation job, get them from HomePro and the like."

[Crossy]

it seems Crossy has uncovered a treasure trove of great generator parts!!!

One aims to please

I wouldn't buy enclosures offshore unless you really can't get what you need here, bulky and expensive to ship.

aliExpress is worth a look for suitable boxes too, many on free (but slow) shipping from China.

If you have a local electrical specialist they often have those harder-to-find items.

[IMHO]

it seems Crossy has uncovered a treasure trove of great generator parts!!!

One aims to please

I wouldn't buy enclosures offshore unless you really can't get what you need here, bulky and expensive to ship.

aliExpress is worth a look for suitable boxes too, many on free (but slow) shipping from China.

If you have a local electrical specialist they often have those harder-to-find items.

In my case, I'll be adding a 3-slot DIN energy meter so I can see what my actual load is (it's handy to know what else you can turn on, or what didn't get turned off), so will need a larger box anyway.

e.g. something like this:

[Crossy]

it seems Crossy has uncovered a treasure trove of great generator parts!!!

One aims to please

I wouldn't buy enclosures offshore unless you really can't get what you need here, bulky and expensive to ship.

aliExpress is worth a look for suitable boxes too, many on free (but slow) shipping from China.

If you have a local electrical specialist they often have those harder-to-find items.

In my case, I'll be adding a 3-slot DIN energy meter so I can see what my actual load is (it's handy to know what else you can turn on, or what didn't get turned off), so will need a larger box anyway.

If you can get one with an external CT (Current Transformer) on a flying lead they're much easier to install than the ones where you have to feed the cable through the unit itself.

EDIT Also nothing to stop you bringing the CT out on a short extension (up to a foot or so) to make it easier to install (just what I did)

[likethemthin]

Thank you for all helpful comments, very good thread!! I am signing off, as usual, everyones comments contributed to me fixing my problem.

Only thing I would add for whatever it is worth, I found my Ford generator at http://www.888powertools.com

Model FG 9250 PE, electric start, 6000 running watts, 7500 max watts (to get motors started.. Everyone will have their favorites, but the Thai owner will ship anywhere and claims to have the parts. Parts are the main issue it seems to me. I chose it because in addition to two smaller outlets, it has one big 32 amp 3 pin outlet that outputs the whole current, which for me worked for hooking up to home electric panel. There are a lot of other brands out there, just what I ended up with. (6000 watts is more than my PEA which many times I feel is down to 2500 watts total!!!).

OK, many thanks again.

[keeniau96]

The 888powertools site looks great, wish my Thai was adequate to get into detail. I did find that coping the model number and googling worked very well to get full details of each item.

Where is the actual location of the shop?

[likethemthin]

The Thai owner at [email protected] will answer email questions in English I believe, but I did have to get a Thai friend to finalize payment arrangements, after I sent my delivery address in English. Specs can be found here for the 50 HZ model: http://www.fordpower.cc/productsshow.aspx?cateid=19&productsid=49

But the 3 outlets I received are as shown on the 888powertools website, 2 smaller ones and 1 big 3 pin 32 amp; not sure why outlets shown different on the above website.

I was able to download a parts list somewhere (English) for what I think is the identical model, FG9250PE .

Also, my supplied Owners Manual is in English; and the exact model number shown on what I received is FG9250P(E)

For people that only need smaller units, the Honda and Yamaha "inverter gens" in which the motor adjust speed depending on load and are more economical are the way to go, but even though those companies make nice big 6000-7500 watt units, the bigger units are not in Thailand and must be special ordered from possibly Hong Kong, not interested in folling with that risk.

[keeniau96]

I hope that likethemthin will post his experience with the delivery, install and initial operation of the Ford genset. I am giving serious consideration to the same unit. Offtopic, slim and thin is best.