Giandel NO Ground-Neutral Bonding

[John Frum]

i dont have an rv, i have a mobile home, trailer, so i need an off grid with a remote control, i wanted a 24 volt model but maybe i can use a 12 volt but i plan on using 250watt panels at 40 vmp or open circuit voltage, can i use 40 volt panels on a 12 volt battery bank and just use large cables to save on losses

Sorry I meant external switching
see "8.9.1 ON/OFF Control Options" on page 51 of this document https://samlexamerica.com/wp-content/uploads/2020/01/11001-PST-1500-2000-12-24_0220_Lrez.pdf
I have this exact model and I control its low voltage disconnect with a Victron battery protect.

As for the panels they are isolated from the rest of the system by the solar charge controller and are as such not a primary factor in your choice of system voltage.

 

[NwCali]

The reason to have a N-G bond is to ensure that if there is a short to the ground wire, the breaker will immediately pop. (This is called clearing the fault).
The reason there should only be one N-G bond is that if there is more than one, current will flow on the ground safety wire.

Its idiotic to not have N-G bonded together in my view.... (unless there is some real reason to not have it).

I guess the people who wrote codes have never been shocked from lack of it..

 

[roadrunner]

Sorry I meant external switching
see "8.9.1 ON/OFF Control Options" on page 51 of this document https://samlexamerica.com/wp-content/uploads/2020/01/11001-PST-1500-2000-12-24_0220_Lrez.pdf
I have this exact model and I control its low voltage disconnect with a Victron battery protect.

As for the panels they are isolated from the rest of the system by the solar charge controller and are as such not a primary factor in your choice of system voltage.

reading it now, thanks

 

[Samueru]

RE: Giandel advised - Ground/Neutral Bonding not supported - floating only - 24V / 3000W PSU

Hi All,
Giandel recently advised me they do NOT support bonding of Ground to Neutral with their 24V/3000W/PSU inverter.

The Tesla charger wouldn't function along with other devices that did soft 5mA pulse to search for neutral/ground connection.

Giandel's advice was to drop a GFCI (essentially becomes ungrounded GFCI like in old houses) - and then the device thereafter. It did trick some of the devices.

That said - I'm likely to abandon and purchase a 48V UL-rated Inverter/MPPT combo that can handle a Neutral/Ground bond near inverter or at whatever panel is used.

Would someone be able to help clarify if the Neutral/Bond limitation is related to High-Frequency vs. Low-Frequency Inverter architecture? Is the LF required? I've seen references to some HF units that can hand neutral bond as well, so I'm trying to understand what Architecture/Specification of the inverter conveys that it can handle neutral/ground bonding.

Appreciate the group's knowledge in this regard.

There is nothing wrong with ungrounded systems, people mistake grounding with bonding all the time, it is the later that provides shock protection.

Having an ungrounded system means that it behaves like an isolation transformer, there is only 120V between L and ''N'' (N is not the right term here but you get what I mean) of the inverter, there is no 120V wrt to earth. It does not become something like old homes with GFCI, those are still grounded, just that they lack the EGC for all the bonding, that's the dangerous thing.

Some countries use ungrounded systems for residential (Norway is one), they still have all their stuff bonded with PE, just that there is no voltage between earth and the conductors like with most inverters. Those teslas and whatever that also tests for ground wouldn't work there either (likely that test function is disabled there).

Interesting, without a N-G bond the ground wire in your AC wiring is of limited value. A short to the ground wire will not clear the fault.


I see no reason why it would be a HF/LF thing. I think it is more of a good/bad design thing. However, the low frequency inverters tend to be higher quality, more expensive and better made so I can believe that they would more likely to have better designs.


My experience is that a lot of the low cost inverter makers are almost criminally negligent in explaining how they deal with N-G bonding.

If you have a fault in a ungrounded system you just accidentally grounded the system, there is not risk with that. For large scale industrial applications where they use ungrounded systems for reliability (they don't want a ground fault to turn everything off) they would add a ground fault detector with an ungrounded system (in this case the ground fault detector is nothing like and RCD or GFCI just in case), if there is a fault a light turns in a panel indicating the personnel that they need to fix it before there is another ground fault that would result in a short circuit and the system going down.

 

[NwCali]

20+ years ago I remember the two not being combined and we'd get a pretty good jolt on some conduit from a short that since the ground wasn't bonded it wouldn't throw the breaker. I don't remember the specifics unfortunately (20+ years ago). When I called the electricians in they explained why it didn't trip and per my request that transformer had the ground/neutral bonded...."problem" fixed and I knew it was idiotic to not have it that way from the start..

Sorry I don't remember specifics, was 20+ years ago...

 

[FilterGuy]

20+ years ago I remember the two not being combined and we'd get a pretty good jolt on some conduit from a short that since the ground wasn't bonded it wouldn't throw the breaker. I don't remember the specifics unfortunately (20+ years ago). When I called the electricians in they explained why it didn't trip and per my request that transformer had the ground/neutral bonded...."problem" fixed and I knew it was idiotic to not have it that way from the start..

Sorry I don't remember specifics, was 20+ years ago...

 

[roadrunner]

so can an inverter that has gfci plugs on the front be hooked up to a residential home with n/g connected at panel without blowing up inverter.
use a 12/2 plug and hook to inverter, then take opposite end and wire to a double pole on opanel to supply both phases with current, 120 but to make sure to shut off main and all 240 volt breakers except for the one feeding in from the inverter for emergency only in a grid down

 

[John Frum]

so can an inverter that has gfci plugs on the front be hooked up to a residential home with n/g connected at panel without blowing up inverter.

Yes, but best practice is to use an inverter that supports hard wiring.

use a 12/2 plug and hook to inverter, then take opposite end and wire to a double pole on opanel to supply both phases with current, 120 but to make sure to shut off main and all 240 volt breakers except for the one feeding in from the inverter for emergency only in a grid down

Have you changed course from this statement?

Giandel NO Ground-Neutral Bonding

RE: Giandel advised - Ground/Neutral Bonding not supported - floating only - 24V / 3000W PSU Hi All, Giandel recently advised me they do NOT support bonding of Ground to Neutral with their 24V/3000W/PSU inverter. The Tesla charger wouldn't function along with other devices that did soft 5mA...

diysolarforum.com

 

[roadrunner]

no, my panel does not have a G/N bond lug,since its a mobile home it must not have to follow residential codes since it has axles under it and is goverened by motor vehicle, it was built in 1980

 

[John Frum]

no, my panel does not have a G/N bond lug,since its a mobile home it must not have to follow residential codes since it has axles under it and is goverened by motor vehicle, it was built in 1980

I'm struggling to reconcile this statement with anything earlier in the thread.

 

[Tecnodave]

Under the NEC in the USA the mobile home should not have a neutral/ground in its main panel as it is really a sub-panel fed by the meter/main which is located outside the mobile home. In the NEC and all other code sets that i have seen you can bond neutral to ground at one point and one point only. If that mobile home had a POCO feed directly to it in the meter/main then the neutral/ground at the main panel located on the mobile home. Most mobile homes will be fed by a 4 wire cable from a meter/main that is not physically attached to the mobile home. Only when a mobile home is permanately affixed to a foundation does it have a meter/main, in this case it is not a registered motor vehicle and no longer has license plates but becomes a “manufactured housing” and is governed by the building department and is taxed as real property. In that case (unusual) (a mobile home converted to manufactured housing) Almost allways the meter main is located on the mobile home.

In every jurisdiction that i have worked in a mobile home is not a building and cannot be served with electricity by the POCO.......ONLY when it is recertified as manufactured housing can the POCO connect power to it., It cant have a Department of Motor Vehicles title at that point, it must be certified by the building inspector as manufactured housing.

The problem with bonding ground to neutral at multiple points is that many electronic devices....computers, referigerator, power supplies etc.....have EMI/RFI filters which filter noise off the hot and neutral legs and short it to ground....if neutral and ground are bonded at several points it will create circulating currents which GFCI devices will “see” as leakage currents and will trip off power to the circuit affected by that ”noise”.

If you have a mobile home which was designed for an external power feed from the POCO but you have converted it to off grid power only then you need to jumper from the neutral and ground buss at one point and only one point.

There is absolutely no reason not to bond neutral to ground....absolutely no electrical device will be damaged by this grounding of the neutral.

Do you have insurance......read your policy.....if you are in violation of the code set used in your city, county, state, country you insurance will not be vaild and you have just given them a way to refuse your claim. Its very clear in insurance policies that you must be compliant with the NEC, CEC, or any code set accepted in the jurisdiction that you live in.

Wanna talk about worst case........if someone dies due to a non-bonded electrical system that you did or knew about, you could face negligent death charges .......wrongful death....

As someone who has worked around electricity all my adult life i will not even touch such a system....liability, i don't care if you get a permit or not but you will toe the code or i will not touch it. I sleep very good thank you.....

 

[roadrunner]

yup, mines fead by a 4 wire cable, the only reason im posting in here is because i want to have an emergency backup, with an inverter and batteries, i want to switch off main when grid goes down, then turn off all 240 volt breakers, then hookup a cord from inver plug or plugs to a double pole breaker on bottom of panel to supply 120 to both phases, then when grid comes back up, i switch everything over in reverse from what i did, main breaker being last to be switched, a couple people on youtube and in here said if i do it it will fry the inverter, they said they destroyed their inverter, because an inverter cant or does not see a N/G bond or something. but mine is not bonded, i just want to make sure before i kill an inverter. i will never pull more than 20 amps per breaker anyway. but just about all my breakers are 30 amp, single pole, on 12 awg wire.

 

[roadrunner]

Great post Tecnodave

 

[Tecnodave]

@roadrunner

please tell me just what kind of main panel feeds your mobile home....I need the brand, type, meter/main combo, or subpanel and breaker spaces. I just may have a fix that will do this. Square D makes a small panel which can be equipped as a transfer panel that will meet the codes and prevent the hazard of acidentally having both sources on at the same time.
The panel is the Square D “QO” line QO 8-16L100 . this panel can be equipped with two main breakers that are toggled togather so only one source can be switched on. There is some special hardware to accomplish this including a toggle that interlocks the two breakers and two breaker lockdowns that are required when backfeeding the breakers.

There are two ways to do this, one is to power up a few circuits from the auxillary subpanel the QO8-16L100

for this method you would mount this panel next to your existing main in the mobile home and route all the nessecary circuits to this panel, one of the backfed mains will be fed from the existing panel and the other will be fed from your generator or off grid inverter. That occupies the left most 4 spaces with two QO 2 pole main breakers, that leaves the right 4 spaces open to use 4 ea QO twin breakers such as the QOT1515 or QOT2020 giving you 8 circuits that can be powered by the POCO or your standby power source or you could use single circuit distribution breakers such as the QO 115 or QO 120, one pole 15 or 20 amp breakers. All of the circuits in the original distribution panel will be powered only by the POCO, all of the circuits in the QO transfer panel can be powered by the POCO or by your standby source.

Second method.....install this QO panel in the circuit between the meter main that feeds the mobile home and the mobile home distribution panel. Remove the feed wires L1&L2 only from the existing distribution panel and connect the POCO feed to one of the main breakers in the “transfer panel” back feeding that breaker......the input goes to what would be the output side of the breaker.....hence “back-feeding the breaker” the inverter output goes to the other back fed main breaker, they MUST be in the left most spaces.....connect the normally input lugs (which now becomes the output of the “transfer panel” The former input lugs of the panel are now the output lugs and are wired from these lugs to the main breaker in the existing distribution panel. DISADVANTAGE OF THIS METHOD.....All use will be limited by the “transfer panel capability“ and the breakers used for the toggle interlocks

WARNING.....Do exactly what i say and you will be safe and within code....Square D has CERTIFIED this panel for backfeeding and offer it in their catalogue. VERY FEW PANELS CAN BE BACKFED THIS WAY....

Square D calls this a “generator transfer panel” and market it with the breaker lockdowns and the toggle lockout mechanism, you will not find the whole assembled panel at Home Cheepo or any normal retailer, its a supplier item

I will include a few photos of an installation that i did in a farmhouse turned into a farm office where the computers must be on 24/7/365 for product tracking. There are also UPS power supplies that keep us powered up before the transfer

The panel on the left is a Square D Homeline 125 amp 20/40 space panel and the small panel on the right is the QO8-16L100 panel.

DISCLOSURE.......Im doing commercial electrical work and am a Square D stocking installer of Schneider Electric including the Square D division, i have information that they do not release to the public.

If you have any questions at all about this procedures PLEASE ASK....im too old to explain why i let you do it wrong...
im very conservative in my electrical work and have never had a system failure and its way too late now to start doing that.....

David

EDIT......i do not have any affiliation with Schneider’s Solar division so please dont ask me about the Solar divisions activities.......Im in the Commercial/Industrial division

 

[FilterGuy]

yup, mines fead by a 4 wire cable, the only reason im posting in here is because i want to have an emergency backup, with an inverter and batteries, i want to switch off main when grid goes down, then turn off all 240 volt breakers, then hookup a cord from inver plug or plugs to a double pole breaker on bottom of panel to supply 120 to both phases, then when grid comes back up, i switch everything over in reverse from what i did, main breaker being last to be switched, a couple people on youtube and in here said if i do it it will fry the inverter, they said they destroyed their inverter, because an inverter cant or does not see a N/G bond or something. but mine is not bonded, i just want to make sure before i kill an inverter. i will never pull more than 20 amps per breaker anyway. but just about all my breakers are 30 amp, single pole, on 12 awg wire.

Please...please...please... Use a transfer switch that prevents you from ever accidentally having both the grid and invert hooked up at the same time.

 

[Tecnodave]

@FilterGuy

Please read my post above about how to do a transfer switch without busting your wallet....you posted while i was still editing that post and i do take my time in such a detailed answer so those hazards do not occur. I have to be very careful as i have been professionally liscensed since 1965, both state and federal and any liar.......lawyer would terrorize me in court for knowingly providing bad information which could injure or cause an untimely death

Be Safe...Be Conservative...Be Alive

David

 

[Tecnodave]

Another note on my budget transfer panel, the whole sheebang is under $100, including main breakers, panel, interlock toggles. If anyone wants to build on of these speak up and i will research the part numbers of the interlocks and backfeed hold down clamps OR go to any Square D stocking dealer and show them the picture, they will fix you right up with the parts or the whole transfer panel, its way cheaper to buy the panel at Home Cheepo and just the toggle interlocks and backfeed holddowns from the distributor. Many distributors will not deal with the public so if i must i do know someone who knows where to get these parts. My distributor will if you know what you need....Royal Wholesale Electric, in Capitola, California

 

[roadrunner]

QO8W-20M100-5,
16 spaces,
wrong cord, i have a 3 wire cord, white goes to 1st phase on panel, black wire goes to 2nd phase, and green goes to the neutral bar, now i have to see if the green goes to neutral on pedestal. but i do have a 6-8 awg solid copper going to ground bar. 100 amp service, mounted to wall in my bedroom, in a raceway 3x18 inches.
It does have a lock out tab above main breaker
Thanks for all the help and responses, trying to do it right
i also rent, so anything i put up will have to come down if i move or landlord will have to pay and allow.
so temp is best but not absolute,
I have been working under an electrical contractor on residential and solar installs, solar edge and enphase systems, so im no newbie, just not sure of backup systems

 

[roadrunner]

I can use this since it will fit also.

SD100XUL Square D QO Generator Interlock Kit 100 amp Main Breaker - - Amazon.com

SD100XUL Square D QO Generator Interlock Kit 100 amp Main Breaker - - Amazon.com

www.amazon.com

 

[Tecnodave]

NOT LEGAL........

you MUST have a 4 wire feed to this SUB PANEL.

The panel is 50 amps...very clear on the cover....

Change the main breaker to 50 amps
Change the 3 wire cord for a SOOW 4 wire cord with 6 ga. conductors
Change the connectors at the feed point to 4 conductors both the outlet and socket.
The proper connector for the cord is NEMA 15-50P and the socket is NEMA 15-50R

The green wire goes to the ground buss located on the right edge of the panels. Connect all the bare wires and green wires to this ground buss. Only the white wires go to the neutral buss installed go to the neutral buss located at the top of this panel.

I did state very clearly my obligation to provide you with accurate information and i have done so, if you choose to ignore my advise , its on you. I warn you again this installation is not legal, its not up to the NEC or any code set that i have ever read. If god forbid you do have a fire as a result of this poor installation you and your landlord could be the target of a lawsuit and more.

Also your insurance is not valid in a non code conforming situation....

VIOLATIONS OF THE NEC THAT I SEE WITHOUT EVEN DIGGING....

50 AMP MAIN PANEL WITH A 100 AMP MAIN BREAKER
60 amp cord with 100 amp main breaker
3 wire power feed when 4 wire is required
no ground on main box


I was editing while you posted....yes that is a Square D generator interlock....the panel must be approved for this interlock as well......there is a clamp and screw that locks the generator breaker to the backplane, be sure that you can affix the lockdown adapter to the backplane, there should be a 8-32 threaded hole in the backplane to accomodate this screw.

This panel has been superseded by a newer model and the generator adapter mounting hole may not be there. These QO breakers have live clips extending from the back of the breaker and they can be live when the breaker is removed from the box, thus the requirement for the lockdown plate and screw.

I am often hired to pre inspect installations for licensed building contractors so they will not get tagged for violations.

Lots of luck getting your landlord to approve these repairs, i know just how tight they are.......I would take one look at this one and get out my ether starting fluid to erase my fingerprints from it and button it up. Being liscensed for soo long i cannot claim ignorance of the laws.

The NEC was written by the NFPA (National Fire Protection Association) not some lame government agency. It was written on the graves of people who died due to unskilled electricians and others who are experts in the feild.