Hello,
I have a 5.6k portable generator and was wondering if the 120VAC coming out of it is considered as good or better a signal than from the power company.
This is because I have just installed a new condensing boiler that uses 120VAC for power for internal components as well as the on board computer and want to be able to run the boiler ( natural gas ) if the power goes out. Right now the boiler is plugged into an outlet that's controlled by a single pole red emergency switch. I want to be able to unplug the boiler from the wall and plug it into a GFI extension cord from the generator if need be.
Thanks for your time.

 

You could put a common mode choke on the output if concerned.
Also is the generator neutral referenced to Earth ground.?
Is that what the GFI is on?
Max.

 

I doubt that your typical generator is going to provide the same quality power as your utility provider.

 

I don't see why not. If you wish you can use a power-bar at has built-in transient suppression filters. In an extreme case, you can install a constant voltage transformer. But be forewarned, they are not cheap. An alternative is to use a UPS which will allow smooth switch-over in a power blackout.

 

A source of mains choke is a 3ph inductor used in the output of a VFD's etc , just use two of the phases.
Max.

 

Thanks for the input, but I'm still not sure.
The generator is on two wheels and two legs, they call it a wheel-barrow kit. So I guess it is earth grounded.
The GFI is just a 12ga. wire extension cord with a GFI box on the end of it, I made for a swimming pool many years ago, don't tell anyone.
Anyways, it sounds like I should run the output through something before the boiler, what's the easiest way to go. This is a portable scenario, so the UPS isn't an option. I'm just looking for some quick signal conditioner I guess. Is the power bar enough? Sorry not up on this kind of situation. Thanks again for your time.

 

The generator is on two wheels and two legs, they call it a wheel-barrow kit. So I guess it is earth grounded.
.

Why would you assume that?
How would it be achieved?
Max.

 

I have a very old (decades) generator to provide power to some circuits on my house. 20 years ago, I ran it with a UPS plugged in. It did NOT like the power from the generator.

Newer generators might be better. I have a newer generator, but haven't tried using it; just not worth the bother unless power is going to be out for more than a few days...

 

The generator is on two wheels and two legs, they call it a wheel-barrow kit. So I guess it is earth grounded.

Old generators won't have neutral bonded to earth ground. Newer ones do, and have GFCI's on the 120VAC outlets.

 

This is a Mitsubishi generator, at least 10 years old.
I'm just learning here Maxheadroom, so sorry about the assumption.
So any suggestions for the AC going to the boiler?
Thanks again

 

Our home like many has no shortage of electronics, many of which like computers are UPS supported. The electronics include our forced air natural gas fired furnace for home heating. The whole house is supported by a natural gas fired automatic transfer 18 KW generator. Prior to that I used a 4 KW (5 KW Surge) gasoline powered generator. None of the house electronics has ever had a problem with the power from either generator and the first was not exactly high end. As to earth grounding? You do not mention location but if in the US and you are tying into or back feeding into a US residence which is up to code earth ground should exist in the residence. If you have concerns go to any home improvement store and buy a ground rod and add it to your connection scheme.

Ron

 

Old generators won't have neutral bonded to earth ground. Newer ones do, and have GFCI's on the 120VAC outlets.

WHY IN THE WORLD do you believe that a generator needs to be grounded??? If it is floating then there is much less shock hazard. IN ADDITION, some fairly current generators that provide a "modified sine wave" do not have either side grounded. A constant voltage transformer of the saturating core type is a good idea bot no, they are certainly not cheap at all. If the furnace controller has a transformer isolated supply then quite probably it will be OK with the generator. If the furnace is still under warranty then now is the time to try, very discretely, of course, in case there is a problem. What happens is that in some situations they use a series capacitor to limit the current, and the generator output, with it's harmonics, winds up delivering a lot more power. This causes destruction of downstream items. So really, a resonant filter is what you need. Noise is usually not the problem.

 

Either way in N.A. safety ground is required according to OSHA.
The common mode choke method reduces H.F. spikes etc.
Max.

 

WHY IN THE WORLD do you believe that a generator needs to be grounded???

It's not what I believe. I'm just stating a fact. My newer generator has neutral bonded to earth ground and I can't use it to power my generator panel until I modify it to break the connection. If I don't, the GFCI's will trip when I connect it to my generator panel.

The 240VAC outlet isn't bonded, so I could use that if I made up a custom cable.

 

MisterBill2....I like the logic of trying something while it's still under warranty, but it's also mid-winter here and that factors into just finding out what I could use to safely deliver 120VAC to the boiler.
There's been a lot of cool/helpful input here but my level of expertise is getting confused with the options. I thought there would be something simple that would condition the output of the generator that I could get off the shelf, to install pre-boiler.
Thanks again for all the continued input.

 

Hello, I have a 5.6k portable generator ...

5.6k dollars? ohms? RPM?

 

Either way in N.A. safety ground is required according to OSHA.
The common mode choke method reduces H.F. spikes etc.
Max.

Closing the connection to ground on an otherwise floating circuit assures the possibility of a shock relative to ground. The osha folks can only recite their scripts, they don't think.
Consider that if there is no ground connection then there would not be any current flow if a grounded person touched an energized wire. Circuit theory tells us that if the path is not completed then current will not flow. So the fixation about grounding does in fact create the shock hazard. And I am aware that the unthinking rules always assume that the white wire is tied to earth ground, even in systems where it is clearly NOT tied to ground. And in this case I am calling ground the potential of the dirt underfoot, and of those things connected to the dirt.

 

WHY IN THE WORLD do you believe that a generator needs to be grounded??? If it is floating then there is much less shock hazard. IN ADDITION, some fairly current generators that provide a "modified sine wave" do not have either side grounded.

You have to be careful with grounded and earthed and also isolation, of sorts and where the neutral/ground bond is made.

My point is, powering a house is different than powering a single entity.
Single entity: ground/neutral bond at the generator.
the whole house: ground/neutral bond via the existing house method

Flame rectification is between ground.

Aside: If the phase is wrong (e.g. wrong polarity of the secondary on the 24 V), it won't work.

I put a properly rated bi-directional Transorb on the 24 VAC side. Between C and R. I also had to put in a filter so automation stuff worked. The furnace was polluting the power line due to the ECM motor. This was not a generator application.

I'd like to know who is the responsible party in the US responsible for enforcing power line polution?
If the device I purchased http://pdf.textfiles.com/manuals/STARINMANUALS/ETA/Archive/PowerProbe.pdf works I have the ability to measure. Never checked. Documenting (removing the filter and doing before after pics) don't have time to do, but I;d like to nail the company because they are not consumer friendly.

 

Between utility issues and a number of hurricanes, I've used generators to power my house and work many times and for extended periods. All generators are not created equal, some give excellent power others do not. Also some loads are sensitive to noise and others are not. You're going to have to fire it up and give it a test.

 

You have to be careful with grounded and earthed and also isolation, of sorts and where the neutral/ground bond is made.

My point is, powering a house is different than powering a single entity.
Single entity: ground/neutral bond at the generator.
the whole house: ground/neutral bond via the existing house method

Flame rectification is between ground.

Aside: If the phase is wrong (e.g. wrong polarity of the secondary on the 24 V), it won't work.

I put a properly rated bi-directional Transorb on the 24 VAC side. Between C and R. I also had to put in a filter so automation stuff worked. The furnace was polluting the power line due to the ECM motor. This was not a generator application.

I'd like to know who is the responsible party in the US responsible for enforcing power line polution?
If the device I purchased http://pdf.textfiles.com/manuals/STARINMANUALS/ETA/Archive/PowerProbe.pdf works I have the ability to measure. Never checked. Documenting (removing the filter and doing before after pics) don't have time to do, but I;d like to nail the company because they are not consumer friendly.

In many areas it seems that any who would enforce the noise pollution rules are missing, or occupied with other activities.