JumbleDuck
Well-known member
And your authority for saying this is ... ?
Combine 3 x single phase/220v = 3-phase power?
- Thread starter rolf.nielsen
- Start date
JumbleDuck
Well-known member
True, but you can get a 415v hazard from multiple 240v installations if they happen to be different phases. As you know, I know you know, and you have said before. But we do have some rather inattentive readers in the thread ...
PaulRainbow
Well-known member
Yes, that's how 3 phase works. But if two of the incoming 240v supplies somehow managed to come into contact with one another, circuit protection would blow.
We do indeed have some inattentive readers and some who just don't understand how it works, that's great, or i'd be ut of a job
I do find it frustrating when i keep explaining it and someone who doesn't understand keep telling me i'm wrong
PaulRainbow
Well-known member
For those who think you cannot put more than one 16a supply on a boat, have a read of the mobo forum, where such installations are common place. The link below has some interesting posts in it, particularly if you ignore the argument about unplugging someone elses shore power
A couple of noteworthy posts from jfm at the start of the thread.
Post#6 from superheat, where he correctly states "The only safe way to have two separate supplies on any boat is to keep the entire supplies and distribution systems on board completely separate. Opposing phases of the same supply can never be paralleled. " Which is exactly what i've been saying all along.
I also noticed some comments about using 32a marina sockets with splitter cables (not to be confused with the LBOK), i'd forgotten about this option. This could be used by the OP if he arrives at a marina that only has a spare 32a supply, he plugs the Y cable into the 32a marina outlet and the two 16a plugs into his 16a sockets on the boat (assuming he has it wired how i suggested). So he's got a pretty flexible system, he can connect to 3 phase if available, he can connect to 32a if available (on busy days 32a may well be more available than two 16a), or he can connect to one or two 16a outlets.
2 shore power cables on a Fairline why?
A couple of noteworthy posts from jfm at the start of the thread.
Post#6 from superheat, where he correctly states "The only safe way to have two separate supplies on any boat is to keep the entire supplies and distribution systems on board completely separate. Opposing phases of the same supply can never be paralleled. " Which is exactly what i've been saying all along.
I also noticed some comments about using 32a marina sockets with splitter cables (not to be confused with the LBOK), i'd forgotten about this option. This could be used by the OP if he arrives at a marina that only has a spare 32a supply, he plugs the Y cable into the 32a marina outlet and the two 16a plugs into his 16a sockets on the boat (assuming he has it wired how i suggested). So he's got a pretty flexible system, he can connect to 3 phase if available, he can connect to 32a if available (on busy days 32a may well be more available than two 16a), or he can connect to one or two 16a outlets.
2 shore power cables on a Fairline why?
JumbleDuck
Well-known member
In the days - long ago - when I did some theatre lighting, there was a minimum separation between phases in theatres. Six feet?
VicS
Well-known member
PaulRainbow
Well-known member
From the doc linked in post #106 "there is certainly no restriction on polyphase supplies in equipment enclosures or equipment racks. "
From the AC ISO:
14 Power-source options
14.1 Power for the a.c. system shall be supplied by one of the following means:
a) single shore-power cable, power inlet, wiring and components with a capacity to supply the required designsystem
load;
b) multiple shore-power cables, power inlets, wiring and components with a capacity to supply the required
design-system load;
c) inverter supplying a.c. power from the craft's d.c. system;
d) on-board a.c. generator(s) supplying the required system load;
ISO 13297:2000(E)
© ISO 2000 – All rights reserved 11
e) combination of shore-power cable(s) and on-board generator(s) used simultaneously if the craft's circuitry is
arranged such that the load connected to each source is isolated from the other in accordance with 4.6.
14.2 The shore-power cable(s) capacity alone, or with on-board generator(s) capacity in addition, shall be at least
as large as the required system load(s).
14.3 A.c. generators, where installed, shall be connected to the electrical distribution system as required in 4.6 or
protected in accordance with 4.7.
14.4 The power-feeder conductor from the a.c. generator shall be sized to transmit at least the generator's
maximum rated output and shall be protected at the generator with overcurrent protection devices with a rating
such that 120 % of the generator nominal output is not exceeded.
From the AC ISO:
14 Power-source options
14.1 Power for the a.c. system shall be supplied by one of the following means:
a) single shore-power cable, power inlet, wiring and components with a capacity to supply the required designsystem
load;
b) multiple shore-power cables, power inlets, wiring and components with a capacity to supply the required
design-system load;
c) inverter supplying a.c. power from the craft's d.c. system;
d) on-board a.c. generator(s) supplying the required system load;
ISO 13297:2000(E)
© ISO 2000 – All rights reserved 11
e) combination of shore-power cable(s) and on-board generator(s) used simultaneously if the craft's circuitry is
arranged such that the load connected to each source is isolated from the other in accordance with 4.6.
14.2 The shore-power cable(s) capacity alone, or with on-board generator(s) capacity in addition, shall be at least
as large as the required system load(s).
14.3 A.c. generators, where installed, shall be connected to the electrical distribution system as required in 4.6 or
protected in accordance with 4.7.
14.4 The power-feeder conductor from the a.c. generator shall be sized to transmit at least the generator's
maximum rated output and shall be protected at the generator with overcurrent protection devices with a rating
such that 120 % of the generator nominal output is not exceeded.
Gumpy
Well-known member
Its been an "interesting" thread for me to read as I have worked with three phase supplies up to 800amps and motors for the last 25 years
When I semi retired I didn't have the luxury of a three phase supply in my home workshop which slightly hindered my work until I fitted a unit similar to this;
4KW 8.5A 220V VFD INVERTER SINGLE PHASE VARIABLE FREQUENCY DRIVE NEW | eBay
Worked reasonably well but does need a balanced load and enabled me to service chain hoists at home until I finally retired last year.
So with a bit of jiggery pokery it is possible to get a three phase supply from a single phase
When I semi retired I didn't have the luxury of a three phase supply in my home workshop which slightly hindered my work until I fitted a unit similar to this;
4KW 8.5A 220V VFD INVERTER SINGLE PHASE VARIABLE FREQUENCY DRIVE NEW | eBay
Worked reasonably well but does need a balanced load and enabled me to service chain hoists at home until I finally retired last year.
So with a bit of jiggery pokery it is possible to get a three phase supply from a single phase
Last edited:
DownWest
Well-known member
That was covered further up the thread, and considered by the OP.Its been an "interesting" thread for me to read as I have worked with three phase supplies up to 800amps and motors for the last 25 years
When I semi retired I didn't have the luxury of a three phase supply in my home workshop which slightly hindered my work until I fitted a unit similar to this;
4KW 8.5A 220V VFD INVERTER SINGLE PHASE VARIABLE FREQUENCY DRIVE NEW | eBay
Worked reasonably well and enabled me to service chain hoists at home until I finally retired last year.
So with a bit of jiggery pokery it is possible to get a three phase supply from a single phase
Gumpy
Well-known member
Forgive me for missing it amongst all the other stuff!
DownWest
Well-known member
It's been one of those threads....
Kinsale373
Active member
Apologies if it looks like i'm picking this apart ( i suppose i am, no offence intended), but it does look very much like you haven't read what's been said previously.
I'm not aware of anything that can do this, although i'm not an industrial electrician. It would be a pointless exercise anyway, the only thin on the boat that is 3 phase is the grey water pump, so if such a device existed you'd be creating 3 phase, only to split it back into separate single phase systems one onboard (except for one pump)
Given that the boat is 65 feet and has a long list of electrical equipment, i single 240v supply would be extremely limiting.
Can't argue with this, but it's been suggested several times and the OP doesn't want to change the pump.
Permanently restricting a 65 foot boat, fully loaded with 240v equipment isn't a great idea, IMO. Not only is it too restrictive, it makes the existing 3 phase genset redundant. Post #64 details how to supply the boat with two 16a supplies, when available, and still keep the option of using the genset at sea, when no shore power is available, or when requirements exceed single 16a supply. It also allows the OP to continue using his 3 phase pump. Finally, it allows him to use a 3 phase supply from the marina, when available.
How is a 3 phase genset going to work, now that you've got him to connect all onboard services to a single system ? You also had him change his pump to single phase, so that won't run from the genset. But, more importantly, he already has a 3 phase genset, that powers all of his 240v equipment by splitting the phases, whilst running the 3 phase pump. This is the main reason i asked if you had read the thread
I don't see the OP state or acknowledge that he already has a 3 Phase gen Set, which post is that in ? I see where you deduce that he has. Maybe the OP would clarify this point and specify the KVA of the set.
If he already has a 3 phase gen set which can run the boat , why bother searching around pontoons looking for 3 separate 230V supplies which he will have to ensure are from the 3 separate phases,-how do you do that anyway ! Gets fairly complicated if you need to add credit to 3 meters or buy specific credit cards for each one !
And you misread what I suggested.
I suggested that if the total load could be managed to 16A then combine all 230V equipment onto a single shore 230V supply .
If the load is greater then go for a 3 phase Gen set and leave the wiring as is.
Kinsale 373
VicS
Well-known member
In #69 he refers to " the generator"
JumbleDuck
Well-known member
Interesting, thanks. I think the theatre rule was additional (or a codified one along the same lines) because the electrical demands can be enormous - 200 x 500W lamps would be a small setup - and it wasn't unknown for portable dimmer boxes to use multiple sockets to feed them. Even without such horrors it would probably have been a bad idea to have alternate lamps along a batten running on different phases.
That's all in my distant past now, and I understand it has changed completely, with LED lamps and local control (CANBUS style) making the hairier stuff redundant. When I did some work in the King's Theatre Glasgow in the early 80s they still used brine dimmers for the spotlights ...
PaulRainbow
Well-known member
Post #69
I guess he doesn't want to spend his whole stay in the marina running the genset.
It's clear that the total loads cannot be sensibly run from a single 16a connection. You keep missing the point of multiple inlets, like so many others. Each supply is completely isolated from the others. One connection will power essential services, such as light, battery charging basic sockets etc, another will supply things like the washing machine etc. If everything is wired to a single input there is never an opportunity to have more than 16a.
Starting to sound like a broken record here, so i'm not going to bother to repeat the rest, read back through my previous posts again and you'll see what i'm suggesting.
Alicatt
Well-known member
The boat I'm looking at (Bayliner 285) has 2 shore power lines, one for the domestic appliances and a separate one for the air conditioning and it is a only a little 28ft speed boatFor those who think you cannot put more than one 16a supply on a boat, have a read of the mobo forum, where such installations are common place. The link below has some interesting posts in it, particularly if you ignore the argument about unplugging someone elses shore power
A couple of noteworthy posts from jfm at the start of the thread.
Post#6 from superheat, where he correctly states "The only safe way to have two separate supplies on any boat is to keep the entire supplies and distribution systems on board completely separate. Opposing phases of the same supply can never be paralleled. " Which is exactly what i've been saying all along.
I also noticed some comments about using 32a marina sockets with splitter cables (not to be confused with the LBOK), i'd forgotten about this option. This could be used by the OP if he arrives at a marina that only has a spare 32a supply, he plugs the Y cable into the 32a marina outlet and the two 16a plugs into his 16a sockets on the boat (assuming he has it wired how i suggested). So he's got a pretty flexible system, he can connect to 3 phase if available, he can connect to 32a if available (on busy days 32a may well be more available than two 16a), or he can connect to one or two 16a outlets.
2 shore power cables on a Fairline why?
Was a problem with my fleet of trucks and vans, most gensets are a nominal 230V @60Hz and a lot of the equipment we used took the mains frequency for reference, if you dropped the frequency to 50Hz then the voltage was too low and you would get a brown out in the equipment, as happened after a service.
The genset was run off a PTO from the van's engine, they reset the engine speed to give 50Hz, then I had a lot of equipment to replace first time it was used after that (it was in Brighton, I remember it well!)
In the recording studio where I worked in the late 1970s had a recording meter that monitored the voltage and frequency of the mains, we had to be careful about "things" switching on and off as they could send spikes along the mains that you could hear in the recordings even if those things were in another building on the industrial estate.
The first truck I was taken on to help install the equipment it had a engine driven PTO with a single phase 2KVA generator off of it, split charging from a heavy duty alternator on the engine to a bank of batteries which then went through a rotary convertor from 12VDC to 240V ac @50Hz, then there was a 2KVA genset in the back of the truck, yeah you could plug it in to the mains too
LadyInBed
Well-known member
I can't understand why it's still going on!
pawl
Member
Well I'm retired now, I make no claim to be any sort of expert on anything, my electrical knowledge, such as it is, is only what I've picked up during many years working as a plant maintenance engineer. Designing, building, installing and maintaining control systems for processing lines, both AC and DC, used for the production of plastic raw materials.
PaulRainbow
Well-known member
So, no real knowledge of marine systems ? If you follow the link in post #114 (also noting post #116, you will see that the system i suggest is common place. Some of the posters in the mobo thread own modern multi £million boats, wired exactly as i described.
#117 references the commercial regs for three phase (although they don't directly apply to marine installations) and the ISO that has to be followed with new build boats, both allow such installations.
Boats are unlike domestic or commercial installations. They have a mix of AC and DC and a variety of data systems. Power, on a single boat, can consist of 12v DC, 24v DC, 240v A, 3 phase AC and can be supplied by shore power, generator and/or inverter. It can have several battery banks and several charging systems. I design and install these systems for a living. The suggested installation is very simple, a few contactors and a changeover switch will keep all circuits separate and some RCDs and MCBs will provide more than adequate safety measures. The system is simple, easy to instal, relatively inexpensive and 100% safe, it also complies with all current legistlation, although it sin't required to do so.
Given that this is my day job and i've posted overwhelming evidence to support my suggested installation, it's very disappointing that you and one or two others are still arguing that i'm wrong.
rolf.nielsen
Member
I'm really impressed with the interest in this thread - thanks to everyone for contributing so actively (be nice to each other now though!). Through arguments and counter arguments I have learned even more.
Perhaps I can help summarize in case it has become difficult to get an overview of the many posts:
1) Safety: Any change in installations will be carried out by a licensed electrician. No DIY. This thread is purely for my own education so that I can have a reasonably educated conversation with the electrician, which I'm sure the electrician will appreciate as it will make his job easier.
2) Generator: I confirm I have a 3-phase generator onboard, I can't recall the capacity but it can pull all the boat's systems.
3) Existing wiring: I have one 3-phase shore power supply. Onboard, it splits into 3 single-phase groups that power my 240v systems onboard which include everything from domestic appliances to pumps etc. It also supplies one 3-phase supply to my grey water pump.
4) Shore power supply: I expect to be able to access a single 3-phase shore power supply, or 3 or more single-phase (16a) supplies.
5) My objective: I want to be able to power all the boat's systems regardless of the type of shore power supply I may meet at a marina.
6) My conclusion: The simplest solution is to add 3 single-phase shore power connections that each and separately power each of my 3 onboard groups. For my 3-phase pump I will add a phase converter to the onboard single phase group that runs my pumps that I can temporarily shut off so that the group's full capacity is available for the phase converter. I will try the converter mentioned in post #44 that ramps up the hz so that starting the pump doesn't trip the fuse. If that doesn't work I'll just run the pump off the generator which is however not my preferred solution because it is super noisy. I have noted the suggestions to change the pump but I do not want to do that at this stage. When I say "I" in this part, what I actually mean is that I will have these suggestions in mind as I discuss options with the electrician, but it will be the electrician who will decide on the best and safest option.
I hope this covers any open ends of this thread, if not then please let me know and I'm happy to clarify - it's the least I can do when you all have put so much energy into educating me!
Perhaps I can help summarize in case it has become difficult to get an overview of the many posts:
1) Safety: Any change in installations will be carried out by a licensed electrician. No DIY. This thread is purely for my own education so that I can have a reasonably educated conversation with the electrician, which I'm sure the electrician will appreciate as it will make his job easier.
2) Generator: I confirm I have a 3-phase generator onboard, I can't recall the capacity but it can pull all the boat's systems.
3) Existing wiring: I have one 3-phase shore power supply. Onboard, it splits into 3 single-phase groups that power my 240v systems onboard which include everything from domestic appliances to pumps etc. It also supplies one 3-phase supply to my grey water pump.
4) Shore power supply: I expect to be able to access a single 3-phase shore power supply, or 3 or more single-phase (16a) supplies.
5) My objective: I want to be able to power all the boat's systems regardless of the type of shore power supply I may meet at a marina.
6) My conclusion: The simplest solution is to add 3 single-phase shore power connections that each and separately power each of my 3 onboard groups. For my 3-phase pump I will add a phase converter to the onboard single phase group that runs my pumps that I can temporarily shut off so that the group's full capacity is available for the phase converter. I will try the converter mentioned in post #44 that ramps up the hz so that starting the pump doesn't trip the fuse. If that doesn't work I'll just run the pump off the generator which is however not my preferred solution because it is super noisy. I have noted the suggestions to change the pump but I do not want to do that at this stage. When I say "I" in this part, what I actually mean is that I will have these suggestions in mind as I discuss options with the electrician, but it will be the electrician who will decide on the best and safest option.
I hope this covers any open ends of this thread, if not then please let me know and I'm happy to clarify - it's the least I can do when you all have put so much energy into educating me!
