Can a change over switch (dead band) eliminate the need for a separate isolator?

I know it will work, but will it clear a CoC? 

I fitted this and it satisfied the electrician who issued the COC

It should pass CoC, if (1) it has a disconnect position (center off) and (2) it is correctly labelled.

If an isolator or disconnector is called for, then the switch should have a label where the poles of the switch have a horizontal line.

If a switch-diconnector is called for, then a line and a circle.

 

6 hours ago, rinners said:

Can a change over switch (dead band) eliminate the need for a separate isolator?

I know it will work, but will it clear a CoC? 

How do you intend to apply this as my understanding of eliminating means to remove or not use an isolator if a transfer switch is in play. All depends on your application if it will pass a coc as they have diffrent applications. For instance if you use a transfer switch to connect your generator to the db board you still need the isolator(double pole cb) before the earth leakage to isolate( breaking live and neutral) the entire db board. Should you use the transfer switch and remove the isolator then i will not issue a coc because 1. Your labeling would be incorrect and 2. Inconsistent application to a standardized system ( could cause confusion). Transfer switch isolates 2 diffrent power sources from each other and a isolator disconnect( L+N) a single power source.

17 hours ago, JustinSchoeman said:

It should pass CoC, if (1) it has a disconnect position (center off) and (2) it is correctly labelled.

If an isolator or disconnector is called for, then the switch should have a label where the poles of the switch have a horizontal line.

If a switch-diconnector is called for, then a line and a circle.

 

There is a center off on these one and it would be the very left most switchgear on the rail so could easily label the positions on the left of it. Or use an indicator LED to the right of it, but markings should suffice.

Not sure how visible this is, but there are circles on the contact points 2,4,6 & 8.



 

 

13 hours ago, TaliaB said:

How do you intend to apply this as my understanding of eliminating means to remove or not use an isolator if a transfer switch is in play. All depends on your application if it will pass a coc as they have diffrent applications. For instance if you use a transfer switch to connect your generator to the db board you still need the isolator(double pole cb) before the earth leakage to isolate( breaking live and neutral) the entire db board. Should you use the transfer switch and remove the isolator then i will not issue a coc because 1. Your labeling would be incorrect and 2. Inconsistent application to a standardized system ( could cause confusion). Transfer switch isolates 2 diffrent power sources from each other and a isolator disconnect( L+N) a single power source.

Would use it for a generator, or even inverter circuits. The center position would isolate the circuitry after.
1) the labeling can be changed
2) this is more what I was worried about, but I think it would depend on how clear the labeling is or could be cleared up with an indicator led

From the data sheet, it is not rated for disconnect or isolation, so it should not pass CoC if used in one of those roles.

@rinners This is the type of mts i use fitted in an enclosure with 2 pilot lights red for mains and amber for standby power.

@rinners This is how it is supposed to be wired in a transfer setup take note of the 2 x Double Pole MCB'S before the mts to protect the cables and the mts. The enclosure to be labeled 1. "Fed from db xxxx" 2. "Manual Transfer Switch" 3.Labels on main db " "Aternative power present at all times" 4. In case of emergency both alternative and Grid power to be switched off"  Red pilot light on main db board to indicate the db is live. The picture below is a ATS but the wiring for MTS is the same.

 

Edited May 29, 20233 yr by TaliaB

1 hour ago, TaliaB said:

@rinners This is how it is supposed to be wired in a transfer setup take note of the 2 x Double Pole MCB'S before the mts to protect the cables and the mts. The enclosure to be labeled 1. "Fed from db xxxx" 2. "Manual Transfer Switch" 3.Labels on main db " "Aternative power present at all times" 4. In case of emergency both alternative and Grid power to be switched off"  Red pilot light on main db board to indicate the db is live. The picture below is a ATS but the wiring for MTS is the same.

 

So if I use the SFT240 I need 2 isolators, but if I use the SF263 and label everything I can use it to isolate and disconnect the inverter and generator? This is for transfer between 2 backup sources

3 minutes ago, rinners said:

So if I use the SFT240 I need 2 isolators, but if I use the SF263 and label everything I can use it to isolate and disconnect the inverter and generator? This is for transfer between 2 backup sources

No like @JustinSchoemansaid it is not rated for transfer or disconnect. You need to use SF263 or similarly rated in conjunction with mcb disconnects as in the picture. Unfortunately their is no shortcuts safety is a first priority. No offence but if you are not electrically qualified please get a qualified electrician to do the wiring you will in any case need a new coc for the partial changes made to the bd board.

2 minutes ago, JustinSchoeman said:

 @rinnersAnd there you have it.

11 minutes ago, TaliaB said:

No like @JustinSchoemansaid it is not rated for transfer or disconnect. You need to use SF263 or similarly rated in conjunction with mcb disconnects as in the picture. Unfortunately their is no shortcuts safety is a first priority. No offence but if you are not electrically qualified please get a qualified electrician to do the wiring you will in any case need a new coc for the partial changes made to the bd board.

Just trying to make sure everything can fit in the DB first, space is tight.

Appreciate all the input.

Edited May 29, 20233 yr by rinners

Not personaly against you @rinners just some information regarding what is currently happening in the electrical industry in South Africa. Below a extract from ECB documentation.

 

"The SA Fire Protection Association tells us that 35% of all fires have an electrical origin.

The South African Insurance Association informs us that in 2018 fire damage amounted to R3bn per annum. This figure was only  R1bn in 2009. What is the cause? 

There is a belief between us all that it is due to poor workmanship, non-compliant materials available on the SA market due to the lack of policing.  Incorrect choice of materials, lack of understanding that electrical installations have to be correctly designed and therefore the installers have to be correctly educated and trained  in the design of electrical installations. Research is currently being performed to clarify this."

Ya best to be educated enough to try and help avoid these types of issues

2 hours ago, TaliaB said:

@rinners This is how it is supposed to be wired in a transfer setup take note of the 2 x Double Pole MCB'S before the mts to protect the cables and the mts. The enclosure to be labeled 1. "Fed from db xxxx" 2. "Manual Transfer Switch" 3.Labels on main db " "Aternative power present at all times" 4. In case of emergency both alternative and Grid power to be switched off"  Red pilot light on main db board to indicate the db is live. The picture below is a ATS but the wiring for MTS is the same.

 

Are these types of Asian origin automatic transfer switches up to standard for SA? More specifically the din rail versions

3 hours ago, rinners said:

Are these types of Asian origin automatic transfer switches up to standard for SA? More specifically the din rail versions

Yes they are good ATS,s rated voltage 400v @ 100a short curcuit current 50ka

W2R-regular-Automatic-Transfer-Switch（ATS）User-Guide.pdf

Edited May 29, 20233 yr by TaliaB

6 minutes ago, TaliaB said:

Yes they are good ATS,s rated voltage 400v @ 100a short curcuit current 50ka

W2R-regular-Automatic-Transfer-Switch（ATS）User-Guide.pdf 2.37 MB · 0 downloads

And do they have mechanical interlocking or a dead band while switching? Can they be switched under load?

3 hours ago, rinners said:

And do they have mechanical interlocking or a dead band while switching?

Yes

3 hours ago, rinners said:

Can they be switched under load

Yes

@TaliaB Which isolators have appropriate C curve? Sounds more like a breaker to me. Do they not mean disconnector as breaker, rather than isolator?
 

23 hours ago, JustinSchoeman said:

 

Those are 2 separate points - you need a C curve 63A CB AND an isolator (although they can be the same device if the CB is isolation rated).

@TaliaB 

I ordered one of these and the mains + generator version came. I was told they are all the same but I'm seeing some back feed or something when changing from backup to grid feed.

https://www.takealot.com/2-pole-63a-automatic-dual-power-transfer-switch/PLID91672797

There is an Onesto DIN LED indicator from the main feed. When the grid feed isn't present and I have the unit in the backup position and then switch it back to grid (still not present, ie LED isn't on) then the mains grid LED lights up for a split second.

Does this mean the interlock isn't working and it's allowing current to pass back to the grid feed? Or is there some residual inductance or something in the cables that causes the LED to light up?