Castanet
-
Hi.
I am off grid, UK. There is no grid tie or connection and there is currently no potential for connection.
Background: I use a Honda EU10i for light duty stuff and have been using an old 5kVA diesel lister single for heavy stuff. The lead to the workshop just manually plugs into whichever one I'm using. The extension lead set-up has evolved into some permanent sockets on a rudimentary ring main for fixed tools/machinery. Most of the stuff is low power so the Honda gets most use. It also charges the independent 12V system with a 25A charger and can do this at the same time as powering some of the lower wattage stuff. The spec for the Honda is floating earth but I don't know the arrangement for the lister single. They both have earth spikes connection and I use an independent piggyback RCD on the extension lead. I am now told the RCD doesn't work with the floating earth type of genny.
Problem: I have a third generator (a very hefty old Lister Petter LPW4) that I want to use to power my mig welder (UK domestic 13A plug) because it has more grunt and a more massive flywheel than the single and is electric start. The 4 options on the sticker inside the lid of the connections/control box on top of the alternator are series star 3ph 4w, parallel star 3ph 4w, series delta 3ph 4w and parallel zig-zag 1ph 3w. Mine is none of these and is connected as follows.
![[ElectriciansForums.net] Off-grid earth connections and safety for both floating and TN generators.](https://www.electriciansforums.net/attachments/lpw4-connection-png.42759/ "[ElectriciansForums.net] Off-grid earth connections and safety for both floating and TN generators.")
Luckily the ends of the wires from the windings have ID ferrules on the crimped terminals. It looks like it's 1ph 240v double delta.
![[ElectriciansForums.net] Off-grid earth connections and safety for both floating and TN generators.](https://www.electriciansforums.net/attachments/lpw4alt-jpg.42760/ "[ElectriciansForums.net] Off-grid earth connections and safety for both floating and TN generators.")
Q1. Is any one able to confirm that connection arrangement? Just worried why that's not included on their list - is it extra dangerous?
I need to check the earthing/safety. I have taken the liberty of cleaning up and re-making some earth connections that were a bit rusty/corroded. I started looking into this a while back and got bogged down with centre-tapped explanations and all that sort of stuff and half of it was probably foreign spec stuff and generally ambiguous. I have followed the earth wires through and note that there is a common earth bonding incorporating all of the following:
Socket Neutral
Socket Earth
Wire U6!
Brass earth/ground spike
Trailer chassis
Alternator case
Controller circuit board backplate*
12V negative/earth **
And possibly the start key/aluminium housing (and therefore me!!)
* This is on rubber anti vibration mounts so isolated but there's a link cable across to the main casing.
** By default as engine bolted to both the 230V and 12V alternators. The generator 12V start system is NOT part of the 12V domestic system.
Q2. Is this a regular generator earth circuit as designed?
Q3. Is this normal practice to have me thus connected to the circuitry at U6?
Q4. What is the best protection for both generator operator and welder operator?
There is no inbuilt RCD or other user-protective system. I have heard reports of RCDs being ineffective in some generator configurations. I looked into it but got confused. This is important if the metal I'm holding with one gauntlet while welding with the other is linked via the weld earth clamp or ultimately the nozzle tip during operation. It is more important if I'm lying on a potentially damp workshop floor when welding although this activity can be avoided if deemed to be too foolish. I have been known to weld outside in the snow in an emergency!
Q5. Do in-line RCDs (ie the ones you just plug in the 3-pin socket and piggy-back your appliance onto like when using the electric lawn mower) work with the LPW4 generator thus configured?
If it is relevant then the controller is connected 7/8 thus
![[ElectriciansForums.net] Off-grid earth connections and safety for both floating and TN generators.](https://www.electriciansforums.net/attachments/altreg-jpg.42761/ "[ElectriciansForums.net] Off-grid earth connections and safety for both floating and TN generators.")
There is some talk of modifying small generators from floating to TN protocol as per paragraphs 5&6 of the following web page
Generator Frequently Asked Questions (FAQ) - https://www.justgenerators.co.uk/generator-faq.html.
"Most buildings now have an RCD built into the consumer unit. This is configured to operate from the mains supply with an earthed neutral, and not from a generator with a floating earth. To utilize this protection device, it is necessary to modify the generator so that it is configured in the same way as the mains supply. This is a simple modification for a qualified electrician, involving adding a link wire from the neutral terminal to the earth terminal. It is recommended to make this connection in the plug that is to be used to connect to the generator. This ensures that the generator is unmodified when it is disconnected from the house, and therefore remains safe.....The plug should be labeled “Do not connect to mains: Neutral-Earth link fitted”. The lead between the generator and the transfer switch is not protected by the RCD, it is therefore recommended to use a steel armored cable for this connection. Finally a local low-impedance earth spike needs to be installed."
Q6 What is the wisdom of connecting the earth and neutral of the small Honda generator so that all generators are consistent protocol?
Sorry there are so many questions but I need to be thorough.
Thank you in advance for any discussion. X
I am off grid, UK. There is no grid tie or connection and there is currently no potential for connection.
Background: I use a Honda EU10i for light duty stuff and have been using an old 5kVA diesel lister single for heavy stuff. The lead to the workshop just manually plugs into whichever one I'm using. The extension lead set-up has evolved into some permanent sockets on a rudimentary ring main for fixed tools/machinery. Most of the stuff is low power so the Honda gets most use. It also charges the independent 12V system with a 25A charger and can do this at the same time as powering some of the lower wattage stuff. The spec for the Honda is floating earth but I don't know the arrangement for the lister single. They both have earth spikes connection and I use an independent piggyback RCD on the extension lead. I am now told the RCD doesn't work with the floating earth type of genny.
Problem: I have a third generator (a very hefty old Lister Petter LPW4) that I want to use to power my mig welder (UK domestic 13A plug) because it has more grunt and a more massive flywheel than the single and is electric start. The 4 options on the sticker inside the lid of the connections/control box on top of the alternator are series star 3ph 4w, parallel star 3ph 4w, series delta 3ph 4w and parallel zig-zag 1ph 3w. Mine is none of these and is connected as follows.
Luckily the ends of the wires from the windings have ID ferrules on the crimped terminals. It looks like it's 1ph 240v double delta.
Q1. Is any one able to confirm that connection arrangement? Just worried why that's not included on their list - is it extra dangerous?
I need to check the earthing/safety. I have taken the liberty of cleaning up and re-making some earth connections that were a bit rusty/corroded. I started looking into this a while back and got bogged down with centre-tapped explanations and all that sort of stuff and half of it was probably foreign spec stuff and generally ambiguous. I have followed the earth wires through and note that there is a common earth bonding incorporating all of the following:
Socket Neutral
Socket Earth
Wire U6!
Brass earth/ground spike
Trailer chassis
Alternator case
Controller circuit board backplate*
12V negative/earth **
And possibly the start key/aluminium housing (and therefore me!!)
* This is on rubber anti vibration mounts so isolated but there's a link cable across to the main casing.
** By default as engine bolted to both the 230V and 12V alternators. The generator 12V start system is NOT part of the 12V domestic system.
Q2. Is this a regular generator earth circuit as designed?
Q3. Is this normal practice to have me thus connected to the circuitry at U6?
Q4. What is the best protection for both generator operator and welder operator?
There is no inbuilt RCD or other user-protective system. I have heard reports of RCDs being ineffective in some generator configurations. I looked into it but got confused. This is important if the metal I'm holding with one gauntlet while welding with the other is linked via the weld earth clamp or ultimately the nozzle tip during operation. It is more important if I'm lying on a potentially damp workshop floor when welding although this activity can be avoided if deemed to be too foolish. I have been known to weld outside in the snow in an emergency!
Q5. Do in-line RCDs (ie the ones you just plug in the 3-pin socket and piggy-back your appliance onto like when using the electric lawn mower) work with the LPW4 generator thus configured?
If it is relevant then the controller is connected 7/8 thus
There is some talk of modifying small generators from floating to TN protocol as per paragraphs 5&6 of the following web page
Generator Frequently Asked Questions (FAQ) - https://www.justgenerators.co.uk/generator-faq.html.
"Most buildings now have an RCD built into the consumer unit. This is configured to operate from the mains supply with an earthed neutral, and not from a generator with a floating earth. To utilize this protection device, it is necessary to modify the generator so that it is configured in the same way as the mains supply. This is a simple modification for a qualified electrician, involving adding a link wire from the neutral terminal to the earth terminal. It is recommended to make this connection in the plug that is to be used to connect to the generator. This ensures that the generator is unmodified when it is disconnected from the house, and therefore remains safe.....The plug should be labeled “Do not connect to mains: Neutral-Earth link fitted”. The lead between the generator and the transfer switch is not protected by the RCD, it is therefore recommended to use a steel armored cable for this connection. Finally a local low-impedance earth spike needs to be installed."
Q6 What is the wisdom of connecting the earth and neutral of the small Honda generator so that all generators are consistent protocol?
Sorry there are so many questions but I need to be thorough.
Thank you in advance for any discussion. X
