Any Electricians here?

[Rock]

After being without mains power for a week during the recent Cyclone in this region, I bought a Generator with the intention of being prepared in the future.
It is a pretty standard 3.5KVA (3000w running) open generator with a Briggs & Stratton motor. It has 2X 15amp outlets and a Safety Switch that the maker calls "RCB - Residual Current Breaker, and OPD - Overload Protection Device.

My intention was always to have an input socket (and associated safety switches etc) installed on my household power board so that in the event of an outage, I simply ensure that the Mains supply is switched off and the generator is then connected to the power board by an extension-lead and supplies selected household appliances/systems, selected by simply switching on in the usual way (ensuring one does not overload the generator)

My Electrician wired up the household power-board but on inspecting the generator, said that the presence of the Safety-switch on the generator would 'trip-out' the generator as soon as it was started and detected the household power-board.

Unbelievably, I cannot get any concensus on this among the supplier, my electrician, other electricians, the product Tech-support, or a number of other tradesmen to whom I have spoken.

Any Electricians/Electrical Contractors/Electrical Engineers here like to comment?

[SUBversive]

Above my pay grade but can you dry run (possibly turning off the main breaker.) the set up and see if the generator trips? That may not work if you have to turn the main back to access the generator.

[mike@ec]

I was actually thinking of doing the same thing on my house that they are in the process of building.

I wanted to wire up a generator to fire up by pressing a switch by the main fuse box

[MonBK]

A 3,5KVA to fire up a house?

I think you need at least a 15K to do so

[SrFADE]

Originally Posted by MonBK

A 3,5KVA to fire up a house?

I think you need at least a 15K to do so

True. The generator you have will be only be adequate for critical items such as freezer, refrigerator, and a few lights. Your building codes may be different, but here in the USA the National Electric Code Requires a transfer switch between the genset and you main power board. It is extremely dangerous to directly power your electrical panel from the genset since it could reverse energize the incoming line (if the mains were switched back on) potentially shocking workers doing repairs. I have a transfer switch (for my 10kva backup generator) as part of a sub panel that only has the critical few circuits on it that I need. You should google the transfer switch and make your electrician read the results.

[crew]

Originally Posted by MonBK

A 3,5KVA to fire up a house?

I think you need at least a 15K to do so

3.5 kva will run a limited number of home functions, and not simultaneously.
7.5 kva will continuously run a gas fired furnace, refrigerator and some lights
15 kva will run a whole house (3500 sq ft) including central air. You could get by with less by giving up some functions.

[kaseri]

It sounds like you are trying to implement a sort of manual transfer switch. That being said you may in fact trip the generator if you try and implement it into your main panel.

The better way to implement this would be to identify the circuits you want powered by the generator and move those circuits to a sub-panel which has a switch that disconnects it from your main panel.

The sub-panel will be fed from the main panel under normal conditions. When main power goes down you throw the sub-panel switch which isolates the the circuits you want powered from the generator. Then you connect the generator to the sub-panel circuits and turn on the generator. This will power only the circuits on the "generator sub-panel".

When your main power comes back up the circuits in your sub-panel are still completely isolated and will prevent feeding back into the main panel. You then shut down and disconnect your generator from the sub-panel and throw the switch on your sub-panel to reconnect the feed from the main.

[77T]

The RCD won't accept voltage variances - especially in the ground potential between the house wiring and the ungrounded generator.

It isn't convenient but since you'll be powering just a few devices, you might use standard extension cords. That way the generator's breakers become the "main".

The biggest limitation for long-term use (e.g., beyond 1-2 days) is access to fuel and the refueling risks.

[Andad]

I have discussed this with my Project Manager/electrician.

I have PM'd my mobile number. Give me a call when convenient.

Eddie.

[Rock]

Thanks for your comments. Much appreciated.
The household Power-board has been wired by the Electrician with a 3-way Safety Switch to isolate the Mains when the Genni is used, but I haven't 'tested' the set-up as I do not want to use the Gennie (fill it with oil & fuel) until I am certain that I will not be asking the retailer to take it back.
As to 'capacity' - I bought this specific capacity as I have not needed a back-up genni in 63 years and probably won't need this one either, except in the unlikely event of another major natural disaster that takes out the mains power for days.
I really only want to run two fridges and a freezer (Max 500w + 500w + 500w) and the extra capacity is a bonus that will allow me to run a few lights, fans & TVs/computers which are not big consumers of electricity. Fridges do not draw power continuously and therefore at any time I should have substantial unused capacity. I would not be using stoves, microwaves or Electric Jugs which all draw substantial wattage (1000w+)
I did want it 'wired-in' however as I want the flexibility of having access to all appliances at my discretion rather than a maze of 'spaghetti' out of a power-board.

[subtona]

once got electrocuted with a visit to the ER… BE CAREFUL and good luck.

[GB-man]

Originally Posted by SrFADE

True. The generator you have will be only be adequate for critical items such as freezer, refrigerator, and a few lights. Your building codes may be different, but here in the USA the National Electric Code Requires a transfer switch between the genset and you main power board. It is extremely dangerous to directly power your electrical panel from the genset since it could reverse energize the incoming line (if the mains were switched back on) potentially shocking workers doing repairs. I have a transfer switch (for my 10kva backup generator) as part of a sub panel that only has the critical few circuits on it that I need. You should google the transfer switch and make your electrician read the results.

I have the same set up. Came with my house and the scariest moment of my life was manually overriding the transfer switch with what looked like an allen wrench (the actual tool used for manual override) with the sub panel cover removed

And believe me, I have done plenty of questionable things in my short life. My soon to be father in law told me best when we were remodeling my house. Something along the lines of "make a mistake on the 120V line and you might be killed, make a mistake on the panel and you WILL die tom

Long story short, I am done doing panel work at home...

Originally Posted by subtona

once got electrocuted with a visit to the ER… BE CAREFUL and good luck.

Scary, I have taken a handful of 120 shocks and repercussions were limited to oh sheet moments. No need to do this work in house, for some reason I enjoy wiring.

[dba]

Wish I could help. All I know about electricity is when the switch is up, the light is on; unless it's the switch at the other end of the hall.

[Rock]

The big surprise to me was the total lack of agreement by so many 'qualified' people as to whether the proposed 'set-up' (generator hooked up to input plug in the Mains Power Box) was acceptable and would work.
Nobody mentioned the issue until I started 'digging' after my Electrician expressed the opinion that it wouldn't work.
The Agent for the generator refused to explain why it wouldn't work, simply stating "These generators are not meant to be used in that context". From what I can gather there are not any generators that ARE intended to be used in that context.
It appears that they are only meant to be connected via a multi-socket power-board to the appliance(s).

[SUBversive]

These generators are not meant to be used in that context

Sounds like the legal team has been consulted.

[paverman]

If you plan on utilizing a standard "portable" generator, it would be safest to simply use extension cords to the various appliances as a previous poster has stated, that way there is no interconnection between the temporary power and the line power. The best alternative is to install an actual emergency generator that is connected to the house circuit via a transfer switch. The transfer switch detects when line power is interrupted and after a predetermined amount of time (10 seconds or so), the emergency generator is started, the transfer switch is thrown and the power source is switched to the generator. When line power is restored, the transfer switch detects power and transfers power connectivity back to the utility side of the switch. This all happens automatically and safely.
You just need to have the generator to the load you desire to power during an outage.
I live in a rural area and on several occasions over the past 20 years have had some lengthy outages during some winter storm events, some lasting 4-6 days, so I eventually installed an LP powered 45 kW whole house generator. Now when the power goes out in a winter storm, my only worry is whether I have enough LP to make it until the line power is restored.
Do yourself a favor and do it right, it's not worth getting yourself or someone else electrocuted.

[Rock]

Yes Ken, my thoughts exactly. The set-up must be completely safe - for everybody, and problem-free also. If it cannot be relied upon to operate without problems then it does not justify the cost ($1500. so far)
The irony is that I may never need it again in my lifetime, and this is why there is a limit I am prepared to spend. I have already spent more than I intended.
If I am not going to be able to 'hook' it into the domestic circuit then I don't need a 3.5kva generator to power two fridges and a freezer, and I will return it and get a 3 kva that will be cheaper to run and smaller and easier to store.

[SrFADE]

Originally Posted by Rock

Yes Ken, my thoughts exactly. The set-up must be completely safe - for everybody, and problem-free also. If it cannot be relied upon to operate without problems then it does not justify the cost ($1500. so far)
The irony is that I may never need it again in my lifetime, and this is why there is a limit I am prepared to spend. I have already spent more than I intended.
If I am not going to be able to 'hook' it into the domestic circuit then I don't need a 3.5kva generator to power two fridges and a freezer, and I will return it and get a 3 kva that will be cheaper to run and smaller and easier to store.

Sounds like the right decision. Connecting into the existing wiring infrastructure of a home is not a casual project; the downside of an improper installation can be very big. Ultimately, the small number of items that can be run on 3.5 kva is probably not worth the effort. By the way, Honda makes some great portable generators. Efficient, quiet, and they start on the first pull.

[paverman]

Originally Posted by Rock

Yes Ken, my thoughts exactly. The set-up must be completely safe - for everybody, and problem-free also. If it cannot be relied upon to operate without problems then it does not justify the cost ($1500. so far)
The irony is that I may never need it again in my lifetime, and this is why there is a limit I am prepared to spend. I have already spent more than I intended.
If I am not going to be able to 'hook' it into the domestic circuit then I don't need a 3.5kva generator to power two fridges and a freezer, and I will return it and get a 3 kva that will be cheaper to run and smaller and easier to store.

Only you can predict how often you'll need this type of equipment. For me, living in a rural area with the potential of being out of power for an extended period, it was worth the piece of mind to install a whole house generator. It comes with a price, however, which can run much, much higher than the $1500 you're talking about. If your outage situations are rare and short lived, a small portable generator is absolutely the most cost effective way to go. I have to tell you though, that when there's an ice storm and the power goes out, it sure is nice not to have to mess around outside setting up generators and running extension cords. I just sit back and wait for the main power to return while I'm watching TV in a heated house .
Good luck and be safe.

[Rock]

Cheers Guys, I totally understand the different considerations in a cold climate, and of course in a 'rural' location where self-sufficiency is important. We had the opposite problem here after the Cyclone took out the power grid - it was 35degrees Centigrade for a week and the lack of fans and A/C at night damn near killed us all.
I am going to make some enquiries to see if there is a portable generator made to plug into domestic Power-boxes as I am now aware that everything I have seen is NOT made for this. The Safety-Switch (RCD) on the generator is the thing that is the problem. I need one with an Overload Protector but not a Safety Switch as the latter is now installed in my household Power-box.
SrFade - I agree about Honda, but they are more than three times the cost of the one I have- for the same output.