Hello everyone,

Looking for some input from the electricians on the forum, mostly to make sure that the aircon installer does not take shortcuts and what not.

I am looking to install 4 split unit aircons (all 12000BTU), placing the outside units in a single open location on a wall outside.

What are the rules (SANS) for wiring theseinto the main DB? I understand that these are all supposed to have dedicated breakers of 25-ish A in the main db, with a isolator for each unit fairly close (1m?) from the outdoor unit. Outside isolator to be 2P swithcing both neutral and live.

BUT, instead of running 4x cables and having 4x breakers in my main db, can I instead run a single 10-16mm cable to a sub db that I will install somewhere inbetween those 4 units, off say a 60A breaker from the main db?

In this sub db, I will then have 4 DP breakers, one for each of the units? Can this then also be considered an isolator per unit? Or must there be a seperate isolator between the breakers and the units? Asking mostly to understand what would be considered good practice and pass inspection.

Thank you!

Edited March 6Mar 6 by Supergeek

Hi Supergeek,

The NEC (National Electric Code) or equivalent, varies from state to state, county to county.

If I understand correctly, you have (4) 1 ton mini split units that operates on 120Vac? Installation is basically the same, even if it was 240vac.

1) Yes, you can install a small 4 circuit sub panel outdoor to supply power to all four mini split units. If power will be supplied to the subpanel from the distribution panel, you would install an appropriate sized breaker and wires from the main distribution panel to an outdoor rated sub panel, ie a NEMA 3/ 3R. From the sub panel, you would have one breaker per unit. I,e. At the main distribution panel, you would install say a 100 amp breaker, and #2 wire minimum, 1/0 maximum (according to distance and voltage drop in mind). Then at the sub panel four 25A breakers. From the sub panel, 4 branch circuits and one disconnect after each branch, one per each split unit.

2) No, a breaker must not be installed as a service disconnect. So you will need an appropriate diconnect in addition to the sub panel and corresponding breaker per unit. The does not need to be elaborate or excessively complicated, It simply needs to be rated accordingly; with the maximum LRA in mind, the disconnect is merely for serviceability. The most common syle is a reversible t handle. When you pull the t handle out, you flip it upside down and put it back in the disconnect panel. It is highly visible in either position (open or closed). They are almost always configured for 2 pole circuits. You do not want a rotary disconnect, unless it has a lockout feature…

_Loch

Edited March 6Mar 6 by Loch

9 hours ago, Loch said:

a breaker must not be installed as a service disconnect

Why is this? My heat pump has a breaker in the DB and an isolator outside, close to the pump.

I'm confident that there's a good reason, but it escapes me.

12 hours ago, Supergeek said:

Hello everyone,

Looking for some input from the electricians on the forum, mostly to make sure that the aircon installer does not take shortcuts and what not.

I am looking to install 4 split unit aircons (all 12000BTU), placing the outside units in a single open location on a wall outside.

What are the rules (SANS) for wiring theseinto the main DB? I understand that these are all supposed to have dedicated breakers of 25-ish A in the main db, with a isolator for each unit fairly close (1m?) from the outdoor unit. Outside isolator to be 2P swithcing both neutral and live.

BUT, instead of running 4x cables and having 4x breakers in my main db, can I instead run a single 10-16mm cable to a sub db that I will install somewhere inbetween those 4 units, off say a 60A breaker from the main db?

In this sub db, I will then have 4 DP breakers, one for each of the units? Can this then also be considered an isolator per unit? Or must there be a seperate isolator between the breakers and the units? Asking mostly to understand what would be considered good practice and pass inspection.

Thank you!

12000BTU does not require a dedicated breaker in the DB. You can add one if you prefer, but it is not a requirement, I stand to be corrected, so lets wait for the electricians to respond.

17 minutes ago, hoohloc said:

12000BTU does not require a dedicated breaker in the DB. You can add one if you prefer, but it is not a requirement, I stand to be corrected, so lets wait for the electricians to respond.

You are correct. A 12,000 BTU air conditioner does not strictly require its own dedicated Mini Circuit Breaker (MCB) in the Distribution Board (DB) if it is powered via a standard, safe 15A plug point.

1 hour ago, Bobster. said:

Why is this? My heat pump has a breaker in the DB and an isolator outside, close to the pump.

I'm confident that there's a good reason, but it escapes me.

An MCB cannot replace a SANS-required isolator because their functions differ: MCBs provide automatic overload/short-circuit protection, while isolators are manual, heavy-duty switches for safe, visible disconnection during maintenance. Isolators handle higher current loads and provide a clear, secure break to ensure no power is flowing, which MCBs do not guarantee.

5 hours ago, TaliaB said:

You are correct. A 12,000 BTU air conditioner does not strictly require its own dedicated Mini Circuit Breaker (MCB) in the Distribution Board (DB) if it is powered via a standard, safe 15A plug point.

An MCB cannot replace a SANS-required isolator because their functions differ: MCBs provide automatic overload/short-circuit protection, while isolators are manual, heavy-duty switches for safe, visible disconnection during maintenance. Isolators handle higher current loads and provide a clear, secure break to ensure no power is flowing, which MCBs do not guarantee.

OK, so whenever I do something electrical my first move is always to figure out what circuit breaker is supplying whatever I want to work with, and then trip that circuit breaker. Do I read correctly? This may not give me protection?

My exploits are confined to light fittings and wall sockets. I did once poke around inside my heat pump and then I used the isolator, because it was more convenient.

@Bobster.

In layman's terms should an appliance or device not have an isolator switch( breaking live and neutral) and should you feel the need to poke around rather switch OFF the incoming main isolator(labeled MAIN SWITCH) in your db then it is safe. Switching OFF a single pole Mcb in the db board breaks the live wire(red) only and the neutral stays connected, a neutral wire is classified as a live conductor in electrical terms. As the saying goes rather safe than sorry.

Also you need to isolate your inverter feed to all essential backed up curcuits should you be working on backed up curcuits via the output isolator( live and neutral) All in all if you not sure isolate Eskom and Inverter curcuits before poking around.

Edited March 7Mar 7 by TaliaB
Spelling

34 minutes ago, TaliaB said:

@Bobster.

In layman's terms should an appliance or device not have an isolator switch( breaking live and neutral) and should you feel the need to poke around rather switch OFF the incoming main isolator(labeled MAIN SWITCH) in your db then it is safe. Switching OFF a single pole Mcb in the db board breaks the live wire(red) only and the neutral stays connected, a neutral wire is classified as a live conductor in electrical terms. As the saying goes rather safe than sorry.

Also you need to isolate your inverter feed to all essential backed up curcuits should you be working on backed up curcuits via the output isolator( live and neutral) All in all if you not sure isolate Eskom and Inverter curcuits before poking around.

Thanks for the explanation. This explains why last time I was replacing a light fitting I could do what I wanted with the red wire, then got something I wasn't expecting when I grabbed the blue. 😂

8 hours ago, Bobster. said:

Why is this? My heat pump has a breaker in the DB and an isolator outside, close to the pump.

I'm confident that there's a good reason, but it escapes me.

Hello Bobster,

Well firstly, I did not write the NEC; or any pertinent electric codes in any jurisdiction. I only follow the rules as written. Of course I do not mind having that discussion here.

Most electrical inspectors do not like to be challenged; I have learned this lesson the hard way; in my younger days. They are vested with the power of having the final say, and can or will easily stall you project and make your life a living hell. The easiest approach is not to engage in an argument, but instead indicate your intentions to comply; but most importantly, to actually follow through. A lesson hard learned, and one that has never been an issue after the fact; knock on wood… :D

To answer your question: a breaker is not a disconnect; it is a device with the sole purpose of ‘breaking’ an electrical connection if an overload condition should occur. Breaker have a definite number of on/ off cycles and most breakers either have a thermal or magnetic trip circuit. If you were ever curious as to what is inside a breaker, and have taken one apart, there are a significant number of parts. Cycling your breaker on and off repeatedly, causes unnecessary wear on the springs and internal components, and that eventually leads to premature failure...

To better answer your question. The pertinent breaker is often located inside the house. But for maintenance purposes, that is where a “service disconnect” truly shines, and immediately becomes your new best friend. Nobody wants to get shocked or electrocuted because they cannot be bothered to turn off the breaker —-or—- accidentally turning off the wrong breaker in an unlabeled or mislabeled main panel. Even if you have a sub panel outside, what if the breaker that supplies that sub panel should trip?

The service disconnect is a safety device meant to protect the technician and whomever is working on that unit from potentially being electrocuted. At a distance of about 3ft or 1 meter, it is also visibly clear as to which unit it is supplying. It is meant to be a very simple and inexpensive device, with no moving parts which only adds to overall safety, and reliable disconnection.

I am so ecstatic that I longer install or service residential HVAC or commercial high temp, medium temp, low temp and cryogenic (ultra low temp) systems. parallel, split suction (dual temp; medium and low temp combined), cascade tandem and chillers (which operates in a vacuum); a variety of equipment for supermarket refrigeration systems, including the refrigerated display cases, to which the aforementioned systems connect to.

My background is in electrical (licensed), power generation, mechanical systems, followed by refrigeration systems (licensed)… et cetera.

A number of our clients were… well they did not ‘always’ want technicians in their elaborate homes, unless absolutely necessary. Strangely enough, we shared the same common, bilateral sentiment albeit with differing intentions in mind. As such, that service disconnect was an absolute godsend, and always a welcomed sight. I am sure that you might imagine the appeal, and benefits of having a service disconnect installed outside, next to the unit; required by code.

Simply put, a breaker has an inherent number of failure modes, if it should fail (think federal pacific, push-matic and so forth). A service disconnect, literally “disconnects” the aircon unit from any source of power. No power equates to no unwanted surprises or accidents.

For everyone’s benefit: The cost of a basic service disconnect is negligible in the grand scheme of things.

In contrast, what is the cost of someone being electrocuted and/or killed over an unintentional oversight or a faulty “protection device” or equipment that might backfeed power inadvertently? The lack of a proper, required safety disconnect can have dire consequences. The cost of human life (and life in general) is infinite and priceless, and can not, nor should be quantified period.

p.s., I think that I read somewhere that a breaker is not required? Please tell me that I am mistaken. All electrical load requires a breaker. Even if that load is less than .1amp (100 miliamps) such as an LED bulb or a 1 amp Incandescent bulb installed in to an edison base lamp, or one that is installed in a hardwired light fixture, still requires a breaker; the lowest ampacity of say, a GE breaker (General Electric; now a merger with ABB) a common and very standard breaker not only specific to the N America. The absolutely minimum ampacity, for a standard breaker is 15 amps —-and— that lamp, regardless of whether plugged in to a receptacle or hardwired, MUST be connected to that 15amp breaker.

Of course a number of standard frame breakers exists in 15amp: 1) your standard, no frills 15amp breaker, 2) the GFCI (ground fault circuit interrupter), 3) the AFCI (arc fault circuit interrupter) and 4) a hybrid combination of both GFCI and AFCI.

The AFCI/ GFCI “hybrid” breaker is mandatory for all brand new house installations in the State of Florida, with exception to certain appliances (aircon is one such exception). I do not particularly fancy the AFCI or any derivatives thereof. One of my past advocations required me to work with LIVE electricity and troubleshoot a number of live equipment. NOTE: Please do not attempt to work with live power, unless properly trained to do so, and are equipped with the required tools and/or test equipment.

The AFCI is so sensitive; any thing that might constitute as an arc, no matter how small will cause that breaker to trip. It will often trip merely by touching the ground leed. When my brother bought his home, light fixtures were not included; it baffled me for a second, but dawned on me that most home owners would likely replace their lights fixtures or ceiling fans with something else eitherway…

The rules are different in the Virgin Islands; including the historic district. Standard, basler breakers are perfectly acceptable. When I pulled a permit to upgrade the electrical system for my c.1863 pegged heavy frame tenon and mortise cottage, with the ground level built from fieldstone, brick and bonded with quicklime. A 16 circuit panel replaced the trumbull 4 circuit “edison base” circuit panel. The venerable service entrance and meter base were also replaced with all off the shelf components. The only custom made to order item was a 200amp meter base from Milbanks. Due to space constraints between the boundary, and the setback behind the perimeter cornice of my stone wall, I required very specific dimensions: 8” wide which was as narrow as possible, by about 32” tall which was the ultimate trade (tall and narrow). It met all of my requirements, including a built in (replaceable) 200amp breaker. I opted for a ringless meter mount where the meter is locked into place by two springs loaded retainers, instead of the more common retention band. The utility company did not particularly fancy this arrangement, but the electrical inspector had no problems with it whatsoever.

I originally intended to install a 100amp service and meter base, but the inspector strongly suggested that it would be best to install a 200amp service and meter base, in the event of future “upgrades”. I did not require any further convincing: at the time, the cost of 4/0 wire at a complimentary discount rate from my preferred materials supplier, was not particularly significant in 2014. This is no longer the case as of 2025/2026. An obscene cost differential between #2 (33.62 mm2) wire versus 4/0 (107.2 mm2) wire exists . I feel that much more fortunate that the electrical inspector made the suggestion. Of course I do not draw anything near 200amps but it is nice to know that the option exists. I draw just under 50amps when using the washer and dryer. Being that all other components were off the shelf items I installed a 200A GE main panel which came equipped with provisions to add a main breaker, indoors and of course I installed one, for ease of use; nobody wants to go downstairs to the ground level to turn off the outdoor breaker… the same procedure was performed in 2018 after acquisition, and the need to update some absolutely crucial electrical components on this fairly recent acquisition, which happily is located directly across the street. A c.1831, Sommerhus (completed in early 1840s). which is anything but diminutive, it is a sprawling multi story building with an east and west wing, 12 rooms not including the main thoroughfares such as the preentry, the great room, with very large folding doors that can join directly to the parlor, formal and informal dining rooms, pantry, an indoor kitchen, with a massive brick stove and oven, a central courtyard, an east west and southward terrace, a expansive garden, a pool that was added after the fact (original photos from the 1900s shows what appears to be a mausoleum where the pool now stands); I am reasonably certain of this as, comprehensive records suggest that this was Wolf’s late wife (Wolf is a very common nickname for males bearing the name Benjamin). Oddly enough, I already knew this, as I also bear the honorific title (middle name) Benjamin. The grave stone dated 1832 still remains in the garden; I just hope that the mausoleum was not demolished but rather respectfully disassembled stone by stone and carefully reassembled in the Danish Cemetery… number of bathrooms that were added after the fact (some which will be removed eventually), the original detached carriage house, to which a loft was added after the fact, a ‘guard house’ or so I was told, very tall plastered stone walls and 3 gated entryways that encompassed the entire perimeter of the premises, where the main entrance leads to several flights of stairs, and the main floor being the uppermost floor, to the very top. Access to the lower level is via an outdoor walk way or via an indoor staircase. vaulted ceilings easily approaching 20ft high (based on my 20ft ladder) both upstairs and downstairs alike. Very large windows with jalousies and shutters.

It seemed as if a complete floor could have easily built without the excessively high ceilings, but historically, before air conditioning, it was understood that heat rises and why some older homes had higher ceilings. The house is excessive as is and the addition of another storey would be beyond vulgar in my opinion .

A 5ft crawl space between the two floors (there are few discreet hatches on the painted heartwood flooring upstairs) After deciding to enter this “crawl space” while I could mostly stand, at 5’10” had to crouch just a bit. After significant exploration, I encountered a wooden box. I already opened with caution but it was disappointedly empty, until I saw the printing on the box. It read: [illegible] followed by Dangerous and demolition outfits MK 138 mod… I swear that my heart stopped for several seconds. Suddenly I was no longer disappointed but rather relieved…

Again my most recent house was built with field stone and bricks, bonded with quicklime and plastered smooth originally. The crawl space proved invaluable for installing conduits and rerouting my electrical to an optimal location without extensive reworking of the masonry and possible damage to the checkard patterned marble slabs or possible damage to the original wooden paneling, beadboard, moldings or tray ceilings.

Fortunately standard panels and breakers were equally acceptable and were permitted. And all critical electrical circuits were upgraded accordingly, which is why I indicated that each jurisdiction have their own set of rules, in addition to the NEC. While not explicitly necessary, I installed GFCIs breakers for the entire electrical project. The main transmission cable is 4/0, instead of 2/0 which would indeed have been capable of supplying 195amps, except when accounting for distance and voltage drop, 4/0 was most appropriate. 100MCM was considered but all calculations indicated that it would have been overkill. You can always upsize electrical wires but never oversize a circuit breakers as they must be rated for the appliances being installed. If installed in a group through a sub panel, the sum of all appliances, at their maximum ratings must be accounted for. The wire size and the main panel breaker must be sized to accommodate the FULL RUN LOAD AMPS as if all 4 units were turned on and running at full capacity. The easiest way to ensure that you are compliant is to read the specifications of one unit; assuming all 4 are exactly the same, under required breaker specification, simply acquire one for each unit for a total of 4. To ascertain the size of the breaker required at the main panel, multiply the required breaker size by 4. That will determine the required breaker size at the main panel, as well as the required wire size; accounting for distance and voltage drop. Electrical is not complicated and certainly not rocket science. When in doubt, there is no shame in asking questions or reading the codifications

In the 20 years that I have lived here, there have been 2 houses that caught on fire, the conrcrete house was gutted, while the historic heartwood heavy timber framed house burned to the ground. This spit of land (island) is 16 by 4 miles. And formerly known as the Danish West Indies, and as of 1917, the U.S. Virgin Islands. My ties are specifically to the UK as well as the BVI; and to a much lesser extent, also to N. America, by virtue of my parents’ formal union, before my birth. ANYWAYS… Back to the subject at hand:

MCBs are specialized breakers with a specified intended purpose. A MCB, at say 1a comes in a number of distinct variations. The letter that follows determines those parameters: A, B, C, D and so forth, each have a series of distinct trip characteristics… I have a significant quantity of German made Siemens (DIN) or more accurately MCBs and accompanying auxiliary attachments. The C0.5s, C1s, C4s and so forth, are utilized for control circuits only. The GE C63s are utilized for the AC input and AC output of inverters. They are not compatible with DC voltage.

NOTE: The most dangerous equipment to work on are inductive, such as anything with a motor or large step up/ step down transformer. Equipment such as aircon and heatpumps (the compressor is a motor) or anything with a flyback transformer, PT Transformers, current transformers (which will run away and can cause significant damage if inadvertently disconnected from its burden, which is why it must have a grounding block to disable it. Larger solenoid coils, and so forth. I have encountered compressors that have developed an internal short to ground through its body (I never worked on those paralleled 15, 22, or 25hp compressors without a preliminary reading without multi meter in hand); consequently I have also read in the paper, or watched the news, where a number of techs were unexpectedly killed simply for leaning over a shorted compressor. They were killed because they became ‘an active conductor’ in that circuit, where electricity will always take the shortest path, and path of least resistance. Shouldnt the faulty compressor’s breaker had trip? Maybe. Many motors and compressors sit on top of rubber isolation bushings to reduce excess vibration and noise. A breaker in a perfect world might, but a perfect world doesn’t not exist; hypothetically.

Neutral wires are not the only extremely dangerous conductor in a circuit; the lack of proper grounding can be equally dangerous. A 3ph motor does not necessarily or theoretically have a neutral; though in the wye configuration, the central node is the neutral. That is how 3ph gennys derive their neutral conductor, 2ph gennys are configured either in a zig-zag or double delta configuration, and derives their neutral conductor from a common node with a 0 theoretical potential, but this is not a hard rule as it will conduct electricity, passively.

Sorry Bobster, and all, for the long read and slight deviation of the OPs thread.

_Loch

p.s., @Supergeek, your intended setup, which includes 4) 1 ton mini split systems, a sub panel with 4) branch circuits and a service disconnect per each mini split system, is very sound and will more than satisfy your local inspector. While not explicitly stated, did not want to make an assumption, but I think it is more than likely that you 1 ton unit(s) are inverter based. Of course with that said this does not change your preliminary system configuration: even DC motors and compressors are inductive as opposed to a basler resistive load, and your 1 Ton units operates on AC voltage; with a built in AC to DC circuitry, which basically allows your system to ramp up and down accordingly, until your temperature setpoints have been met;

unlike older non-inverter systems or very large systems: 4 stage compressors that in essence bangs on with all four stages active, initiates pumpdown for 30 seconds to eliminate potential floodback, then bangs off and activates one compressor at a time in order to reach maximum capacity prior to the activation of each unloader in an attempt to modulate and maintain the set temperature. Once this is achieved, each compressor deactivates, one at a time, until the unit shuts down and repeats this cycle. This type of system typically has two independent refrigeration circuits (2 suction and 2 high pressure lines with two 7.5 scroll compressors in tandem per circuit, for a total of four compressors that connects to the indoor unit with 4 TXVs or expansions valves. A ducted 30 ton system with a number of control boards, divided between the indoor unit and outdoor unit. Those units required an unfused indoor disconnect, as well as an unfused outdoor disconnect; both disconnects were 3 phase at 200amps and 100amps respectively. They also had breakers: the outdoor unit received power from the utility room and the indoor unit received power from a distribution panel upstairs in the attic.

Good luck!

TBH; that is exactly how I would install a group of 1 ton 12000BTU, split systems. It is worth noting that: once a certified Electrician, the understanding of electricity does not change so dramatically. Ohms law is a universal standard the technical distinctions are basler tediums that are not not terribly relevant and basic attention to detail is required. I,e: 50 (1500rpm) versus 60 hz 1800rpm, the Blue or in some cases, Black leed is typically your Neutral opposed to White or Grey; ground is typically Green or Yellow with a Green tracer (or stripe) vs Green; L1 is typically Red vs Black; L2 is typically Brown vs Red; L3 is typically Grey vs Blue. Voltage differences are typically 220vac vs 230 or 240vac; although most equipment will run on either, as long as it can also operate on 50hz. In fact most modern equipment with a built in switchmode power supply, will comfortably operate on 90vac~240vac as well as 47~63 Hz. In addition to, a number of electronic equipment can be set up to operate on a variety of internal power systems.

NOTE: 12000 BTUs = 1 Ton, imagine working on a 300~400 ton system… per store.

_Loch

Edited March 10Mar 10 by Loch

21 hours ago, Loch said:

Hello Bobster,

Well firstly, I did not write the NEC; or any pertinent electric codes in any jurisdiction. I only follow the rules as written. Of course I do not mind having that discussion here.

Most electrical inspectors do not like to be challenged; I have learned this lesson the hard way; in my younger days. They are vested with the power of having the final say, and can or will easily stall you project and make your life a living hell. The easiest approach is not to engage in an argument, but instead indicate your intentions to comply; but most importantly, to actually follow through. A lesson hard learned, and one that has never been an issue after the fact; knock on wood… :D

To answer your question: a breaker is not a disconnect; it is a device with the sole purpose of ‘breaking’ an electrical connection if an overload condition should occur. Breaker have a definite number of on/ off cycles and most breakers either have a thermal or magnetic trip circuit. If you were ever curious as to what is inside a breaker, and have taken one apart, there are a significant number of parts. Cycling your breaker on and off repeatedly, causes unnecessary wear on the springs and internal components, and that eventually leads to premature failure...

To better answer your question. The breaker is often located inside the house. But for maintenance purposes, that is where a “service disconnect” truly shines, and immediately becomes your new best friend. Nobody wants to get shocked or electrocuted because they cannot be bothered to turn off the breaker —-or—- accidentally turning off the wrong breaker in an unlabeled or mislabeled main panel. Even if you have a sub panel outside, what if the breaker that supplies that sub panel should trip?

My position is very different from yours. I know a bit about electricity, because I used to fix cash registers and the like (they have power supplies), but I'm no electrician.

In this case I was wondering why we have a breaker and then, physically closer to the device, an isolator. A genuine question to address genuine ignorance and confusion/

It turns out I have misunderstood the role of the breaker. And I shouldn't have! How many times have I told people that breakers are there to protect the wiring, not to protect people? And yet I keep on using them for protection. As I said to TaliaB, I recently made a lights circuit "safe" by turning off the breaker. The breaker only turns off the live, and neutral is not there just as a return conductor. As I found out when I grasped a blue wire and got a funny tingling in my fingers.

Thanks for the detailed answer.

Hi there Bobster,

Electronics repair, computer repair and networking, and even electrical, all share several common threads; it is not at all an unusual or unreasonable thought that a breaker might also serve as a disconnect. It is also a very legitimate question. My apologies for the wall of text; it might have been more proper to say: 1) that a breaker is designed to protect your equipment and most importantly, your home. 2) a service disconnect is designed to protect the technician and/or the end user.

Although, I have used breakers in the past, to turn off power to aircon units prior to service and repairs. Oversights happen occasionally, or equipment is installed without the proper permits, safety implementations and inspection, quite often. Truthfully many electricians (including myself) feel that some of the rules and regulations are “arbitrary“ or unnecessary, but sometimes it is far more prudent to choose our battles wisely; especially when the electrical inspector is concerned :D

Take care!

_Loch

20 hours ago, Loch said:

Electronics repair, computer repair and networking, and even electrical, all share several common threads; it is not at all an unusual or unreasonable thought that a breaker might also serve as a disconnect. It is also a very legitimate question. My apologies for the wall of text; it might have been more proper to say: 1) that a breaker is designed to protect your equipment and most importantly, your home. 2) a service disconnect is designed to protect the technician and/or the end user.

It's fine. Thanks. I did get a couple of shocks on my work bench days. We all did. I did know to use a screwdriver to short the HT lead on a CRT to earth before poking around there. We also used to amuse ourselves by inflating a paper bag and bursting it behind somebody's head just as he stuck his fingers into whatever he was fixing. This passed for humour.

I know there is usually a good reason for things like having an isolator as well as a breaker, even if it's not obvious to me. So this was a chance for me to learn something.

Thanks again for the good answer.

Ah yes, a trip down memory lane. Those good, not so old days!

Charging a capacitor and ‘playing’ catch with an unsuspecting comrade. After a few zaps, my brother never trusted me, if I were to say catch 😂. Of course none of my comrades, close associates or especially my brother who is about my age, were never injured or hurt, and even found humor and amusement in it (myself included) after the initial ‘shock’, no pun intended :)

We would also fool around with an old Lincoln AC stick welder, and in a concerted effort would make sure that an unsuspecting fellow, was either touching the work piece, or a point where the ground clamp was attached, and then we would zap them with the stinger. It was in all good fun back then, and as younger men and a bit of joviality… completely innocuous, and we were all equally amused… a light hearted way to start another tedious day.

a slight deviation from the OP topic…

Regards,

_Loch