Hi all,

I'm busy finalising my proposed main DB revamp and wiring layouts, but have a question I cannot seem to find an answer to:

SA Home Distribution Boards generally seem to have the breaker switches running horizontally next to each other in the panel cutouts - is there any reason why they are like this and is it permissible to mount them vertically instead?

Reason for asking is that my current DB is too small and crowded and I want to have an electrician re-wire and re-position certain circuits within the box, as well as add the separate inverter circuits where needed - to do that, I need a much larger DB box, possibly with 2 or 3 panels of breaker cutouts. Given the current DB is recessed and I don't want to break the wall/plaster, my only option is to look at a surface mount DB, however there is not enough room (top and bottom) for the larger surface mount box to be placed directly over the current box, hence I was thinking of mounting it "sideways" over the current box - this means that the 2 or 3 breaker panel cutouts would be vertical.

Is this a problem and if so, why?

1 hour ago, HowardB said:

Is this a problem and if so, why?

From a facebook group I follow with lots of American guys... putting things at 90 degrees of normal is against code. I have no idea what the local rules say. Apparently there is a rule that says if they are vertical, UP must be the on position. Of course mounting them sideways makes this ambiguous, and may well be the reason it will be frowned upon.

Ask a sparky. This is stuff they should know... 😉

6 hours ago, plonkster said:

From a facebook group I follow with lots of American guys... putting things at 90 degrees of normal is against code. I have no idea what the local rules say. Apparently there is a rule that says if they are vertical, UP must be the on position. Of course mounting them sideways makes this ambiguous, and may well be the reason it will be frowned upon.

Ask a sparky. This is stuff they should know... 😉

Thanks @plonkster, just really interested to know - seems common sense is not so common any more - if a breaker shows ON/OFF, which most seem to reflect, imo this would negate the UP-is-on position problem; light switches for example are often not clearly marked (or marked at all) and can be orientated any which way you want, but it seems the DB switches must be in a certain way - all my light switches are down for on and up for off, which kind-of goes against any code that seems applicable in the home electrical circuit requirements.

I'm having a tough time trying to understand some of the local codes and have honestly given up on some things as they just don't make any logical sense to me at all 

Will chat to the sparky about ti when I see him in a few weeks.

9 hours ago, plonkster said:

if they are vertical, UP must be the on position

That could well be the main reason. But also, circuit breakers are delicate mechanical things, and having gravity act 90° different to normal... I just don't like the idea. Especially where safety is involved, and a Distribution Board is nearly all about safety.

9 hours ago, HowardB said:

all my light switches are down for on and up for off

Apples and oranges. Circuit breakers have a specific mechanism for disconnecting on overload, light switches do not. This mechanism should preferably not have to fight gravity. But almost all of them are spring loaded and will work fine even if you mount them upside down... which is why I am unsure about the requirement, whether it is merely for consistency sake (half of safety is not doing weird surprising things people have to figure out first) or if there is a real technical reason.

The operation of a circuit breaker will not be influenced by its orientation (the tripping mechanism will easily overcome gravity 😀).

In specific applications circuit breaker are installed horizontally like low voltage motor control centres with rackable switchgear buckets.

For distribution boards they are installed vertically with the ON/ LIVE / CLOSED position at the top and TRIPPED/OFF/ISOLATED position at the bottom. The is mayor safety issues as you cannot create confusion  - looking at the board  I must immediately know the status of the disconnecting device.

Edited April 25, 20197 yr by Jaws

26 minutes ago, Jaws said:

cannot create confusion

Ah cool, I thought that would be it.

There are some devices that must be mounted vertical (eg fused disconnects), but that is a different topic 🙂

Not the same thing, but I think there are some DC MCB's that are polarity conscious.

Does it matter which way the supply and load get connected to a CB?  In other words, does it make any difference whether one feeds the supply in the top or bottom?

27 minutes ago, dax021 said:

Does it matter which way the supply and load get connected to a CB?  In other words, does it make any difference whether one feeds the supply in the top or bottom?

That is a good question. The way I see sparkies do the work is to always loop it around and feed it in at the top. Again, I think this is a safety-least-surprises thing. Electricians expect the supply to be at the top and the bottom to be dead when the breaker is off, don't surprise them! I don't think it matters on a technical level, not with AC.

ABB even makes breakers with bottom entry options so that when you combine them with others (eg main switch with an RCD next to it) you can save some of the looping, but these are specially designed with insulated busbars that connect them together so that they become a single unit, and again there is no real surprises.

With some DC breakers, polarity is important. They have a magnetic cage inside that is supposed to stretch the arc, and if you connect it the wrong way round it does not work as designed.

Finally, with some changeover switches (eg Hager SF263) the terminals are such that you have no choice but to do bottom-entry.

23 minutes ago, dax021 said:

Does it matter which way the supply and load get connected to a CB?  In other words, does it make any difference whether one feeds the supply in the top or bottom?

For AC, it doesn't matter functionally if the MCB's upside down, otherwise they wouldn't work in Australia.

Seriously though,

Some MCB's are pre-inscribed  with the labels "Line" and "load".

I've only ever seen the top labelled line and the bottom labelled load, and that is also the convention I have always followed.

I can't recall seeing it written down though.

Although they will trip if upside down, there is an unequal amount of force required to switch on and off.

I suppose an object falling on an MCB is likely to be going downwards, and so the tendency would be to turn something OFF rather than ON, and that would be considered safer.

 

Thanks for the answers. 

I am no electrician, although I have wired a few houses, and I always put the supply at the top.  My landlord, on the other hand, always puts the supply at the bottom.  (Notice I have steered far away from terms like "bottom entry", gives me the grills).  He says this is the standard in the UK, but as I wouldn't trust him to wire a 12V light bulb, I am not sure if this is the case.  At least it would appear that it makes no difference to the function of the CB, wired either way.

Thanks guys, interesting.

From a space limitation perspective, I'd prefer to mount the box so the breakers are vertical, but I'll also ask if it could be deemed compliant if the front of the DB/breakers are marked clearly with ON/OFF or IN/LOAD. After reading various articles, most of which don't relate to SA, there seems to be no real technical reason as to why it can't be done, however from a consistency and safety sake it does make sense.

16 hours ago, HowardB said:

Thanks @plonkster, just really interested to know - seems common sense is not so common any more - if a breaker shows ON/OFF, which most seem to reflect, imo this would negate the UP-is-on position problem; light switches for example are often not clearly marked (or marked at all) and can be orientated any which way you want, but it seems the DB switches must be in a certain way - all my light switches are down for on and up for off, which kind-of goes against any code that seems applicable in the home electrical circuit requirements.

I'm having a tough time trying to understand some of the local codes and have honestly given up on some things as they just don't make any logical sense to me at all 

Will chat to the sparky about ti when I see him in a few weeks.

 

Our brains are wired by now that up => ON and down is OFF, so working in dark/emergency this works... now if you go put them left right... then that natural wiring is not going to be sure anymore.

G

 

3 hours ago, georgelza said:

 

Our brains are wired by now that up => ON and down is OFF, so working in dark/emergency this works... now if you go put them left right... then that natural wiring is not going to be sure anymore.

G

 

Makes sense @georgelza.

I think I'm going to have to re-think the placement, or dismantle wall and floor units to accommodate the longer horizontal flushmount box. Otherwise may have to go with 2 or 3 separate flushmount units and try and make them fit.

Howard,

See the thread, My Build, where I removed the old DB face plate and then put my 3 rail box over the hole of the old box.

you get a 2 rail box also.

G

So that would be this one:

https://powerforum.co.za/topic/3385-my-build/

 

Yes

Thanks @georgelza will take a look on the weekend

Is it legal to extract existing circuits wired with GP wire from a DB through the side cover of the DB to new sub DB for UPS purposes