installing switchboard in rack cabinet?

Forums › Home Workshop DIY › installing switchboard in rack cabinet?

greenbone

176 posts

Master Geek

#222445 11-Aug-2017 11:55

i have a network cabinet like this

to keep things simple i would like to install the mains board / switchboard components (breakers / RCD ) on a DIN rail in the cabinet, rather than in a separate enclosure. below the switchboard rail would be some other PLC gear, network switch, hub, etc

any legalitys that says my electrician cant do this? i know theres regs regarding height from floor, enclosure doors being lockable, but cant really find much detail on the enclosure itself

thanks

jimbob79

658 posts

Ultimate Geek

#1845089 11-Aug-2017 12:06

I have a feeling that is would not be allowed, but you can have a Power Outlet in the case.

I understand what you want and why, but a sparky would make the decision has he would need to sign off on the 'Electrical Certificate of Compliance'.

nickb800

2462 posts

Uber Geek

Trusted

#1845092 11-Aug-2017 12:11

My understanding is that it's illegal for non-electrician to 'enter the switchboard enclosure', which you would be able to do in this case, to work on your network cables etc. You would probably need to develop a custom fabricated shield for the electrical part of the cabinet, both to cover the rear of you din rails, but also the front (e.g for an MCB, so you can access the breaker switch but not the screw terminal.

If you really want to go this route, I'd suggest that the best approach would be to have two identical, short, 19" racks stacked. One can be the switchboard, with a panel covering the DIN rails and terminals on DIN mount items, and the other one can be a traditional network rack which you can access as you wish. You could get you sparky to run connecting cables between the two to interface with you PLCs (which I presume is why you want to do this).

Even if it can be done legally, you might struggle to find a sparky willing to sign his life on it, being out of the box and all. Perhaps an industrial sparky (would help with the PLC stuff too)?

jjnz1

1185 posts

Uber Geek

Subscriber

#1845161 11-Aug-2017 13:28

Hi, I wouldn't sign it off for a couple of reasons:

Access is not great, partially impeded
There is a chance the cabinet can get locked, preventing access to the MCB's to turn off the circuit
It is very dangerous having a metal surround that 'could' be used by a homeowner or sparky to climb through to work on the switch board - yes I know the cabinet does hinge from the wall, but there is a chance that with all the equipment in there (or pure lazyiness) an electrician or homeowner would try and service the switchboard through the rack

The solution is to install it next to the cabinet, and install a power outlet inside the cabinet. The power outlet doesn't need an on/off switch if it is that close to the switchboard and clearly labelled.

gregmcc

1837 posts

Uber Geek

Trusted

Lifetime subscriber

#1845264 11-Aug-2017 15:25

Here are the choices.

1) lock it, as the home owner you would not legally be able to unlock it to reset a tripped circuit breaker, it would be call an electrician *everytime*

2) have it unlocked, but install a plastic masking panel so you have access to the toggles of the circuit breakers as you do with a normal distribution board.

Better option is to have your electrician to install a surface mounted distribution board inside the cabinet.

edit:-

forgot to mention there are rules about installing distribution boards in cupboards and cabinets, the use must be for the distribution board only, meaning you cannot install other stuff in it that may impede access

sparkz25

553 posts

Ultimate Geek

#1845388 11-Aug-2017 21:08

i wouldn't sign it off, personally why would you do this? there will be no segregation between any of the lv equipment at all if its all mounted in the same cabinet, there are no masking panels to protect you or any one from touching live parts and when you unlock the cabinet from the frame to open it from the frame the back of the switch board will be exposed

keep them separate, if you read the regs there is a minimum requirement of 300mm segregation between mains wiring and lv wiring

gregmcc

1837 posts

Uber Geek

Trusted

Lifetime subscriber

#1845389 11-Aug-2017 21:15

Looking at what the OP wants the scope of works is way outside what a home owner is legally allowed to do.

richms

23593 posts

Uber Geek

Trusted

Subscriber

#1845391 11-Aug-2017 21:19

Ive seen a few U high din enclosures used in racks to take the giant incoming feed and have a whole lot of individual breakers for different things in the cabinet that needed power. - was like a larger version of a typical rack PDU with a fat black cable coming in and several 16A IECs on the back of it.

Richard rich.ms

andrewNZ

2298 posts

Uber Geek

#1845409 11-Aug-2017 21:53

As well as following the written rules, electricians are also expected to follow "best practices" (vague, I know). IMO, without reading to find actual rules, this fails the best practice test.

If this was a commercial or industrial environment, I MIGHT consider trying to find a way to make it work, IF there was a very strong argument for it (I cant think of any reason I would).
In a residential situation, there is no way I'd consider it.

Reasons against it:
- Too hard to make the enclosure compliant. The short version is, if you can touch the coloured wires the user isn't allowed access.
- Far to easy for the switchboard to be blocked by stuff.
- It's just a bad idea. When you decide in 10 years that you don't like it, it could cost 10k+ to put it into a regular enclosure. Regs change ridiculously often, and changing a board means bringing it up to current rules.

Can you find someone who will do it?
Probably yes, there are plenty of really dodgey sparkies out there.

Electrician.

Location: Dunedin

greenbone

176 posts

Master Geek

#1846159 14-Aug-2017 09:16

my wife said yesterday "lets cut a hole in this wall and put a door to the guest room here, its easier". i said "why would we complicate this wall anymore by cutting another opening in it, when the door can be put here, completely out of sight from the main thoroughfare, yet still remain as functional"

sometimes you dont want to cut another hole in the wall just because its easier. im trying to avoid a separate enclosure installed beside the network cabinet. it will look sleek and cleaner with everything contained in one cabinet, and its that detail that im interested in. hours / cost isnt too much of a factor

perhaps some shielding or other type of separation within the cabinet is the solution here. thanks all for the replies

jjnz1

1185 posts

Uber Geek

Subscriber

#1846332 14-Aug-2017 13:35

(Normally for commercial type applications) you can get a 4-5RU 20-36 way MCB distribution board for both AC and DC.

It will be expensive, but could potentially provide what you are after. It would need a local isolation point outside of the rack, suitable cable management, and would require your rack to be fixed (not swinging), and be suitably seismically restrained.

I would consider this only on a floor mounted rack, where the MCB DB is at a good working height. (At the 35ru? mark for example)

nickb800

2462 posts

Uber Geek

Trusted

#1846443 14-Aug-2017 15:15

This could fit the bill. May be a local version

http://www.eldeco.be/mainsstrips.htm

gregmcc

1837 posts

Uber Geek

Trusted

Lifetime subscriber

#1846484 14-Aug-2017 16:24

nickb800:

This could fit the bill. May be a local version

http://www.eldeco.be/mainsstrips.htm

Getting there, but no neutral and earth bars, so it's a no go.

It can be done, with enough TIME and MONEY, it can also be done for a lot less time and money using a standard switch board