While the wiring and electrical standards in the UK and the Republic of Ireland are broadly similar there are some signifigant differences.
Wiring in Ireland is a sort of hybrid of UK and Northern European systems and the wiring rules used here are not quite the same as the UK standards, but are generally very similar.
The major differences you may notice:
Ireland's distribution system supplies 220/380V, in common with almost all EU countries. The UK on the other hand supplies 240/415V... Appliances are now all rated 230/400V which means that either system is within their spec. This allows equipment to be made for a pan-european market, including the UK.
Irish colour codes are not identical to the UK although they do have the same origins. You'll find legacy installations with black(N), Green (E) and Red (L) cabling however, we moved towards a European standard system a bit earlier than the UK so you'll find a lot more homes with Blue (N) Brown (L) and Green/Yellow (E)
(some VERY old [now rare] installations may also follow other codes)
While ring circuits are permitted here they're not very popular among the electrical trade. The vast majority of homes are wired with radial circuits. Also, all socket outlets supplying up to 32A must be covered by an RCD(since 1980). There are no exceptions to this rule.
Irish distribution panels (consumer units) are not the same as their british counterparts. Historically we've used German VDE standards for fuses, so you'll find old installations have Diazed or Neozed fuses rather than the UK-style re-wirable types. These fusing systems are designed to prevent accidental over-fusing of a circuit by using different sized fuses and fuse holders.
The later versions of those fusing systems were still being installed in the mid 1980s in some instances and are still permitted in new installations. They provide protection that is totally comparable to MCBs and some contractors simply prefered them. They also install on the same boards in the same modular DIN rail installations as MCBs/RCDs.
All consumer units (distribution panels) here must have a main fuse rated at the maximum load for the installation. Breakers are now permitted if they comply with particular codes. (see wiring regs for details) however, in general, a simple single neozed fuse is used.
In terms of regulation of electrical contractors, a regime similar to the UK applies. Contractors should be members of one of the recognised organisations e.g. RECI. You will need to be a member of one of these groups to issue certificates of completion that are recognised by insurance companies / local authorities / ESB (PoCo) etc etc.
RECI etc will set out minimum standards of qualifications that are deemed to be acceptable, carry out inspections etc etc.. basically, it's a case of the industry regulating itself. Same system applies to professions here like accounting, law, medicine etc..
The national wiring rules are available from www.etci.ie
(electotechnical council of ireland) and all installations legally must comply with them regardless of who does them. If the installation doesn't comply with the code the contactor who carried it out would be fully liable for any consequences.
If you check out some of the ITs (Institutes of Technology) you will find courses that would give you a decent grounding (once again pardon the pun) in all aspects of electrical work in Ireland.
If you've already qualified as a contractor in the USA it would simply be a case of learning a different approach to the same problems. There are many differences between European and US installations but, obviously all of the electrical theories would be identical since they're just based on the laws of physics.
Oh yeah forgot this one
All current installations use BS1363 outlets (the same as the UK) and fused plugs. (This is known as IS401 here)
Switch plates / boxes / etc are identical to the UK.
Legacy installations (pretty rare to be quite honest)
Schuko (german style plugs) on 16A circuits or BS546 (round pin UK plugs) on radial 10 and 16A circuits.
That is more of a historical footnote than anything else as those installations are pretty much dead and burried by now.
On the supply side of things:
electrical contractors here do not deal with the power network at all. i.e. you don't run services and you don't have any access to the wiring before the meter.
When an installation's complete the contractor leaves customer tails in a metering cabinet and these are connected to the meter by the PoCo. Any service upgrades / replacement / enhancements etc are done by the PoCo. The most recent installations have a demarkation point (an isolation switch) after the meter.
In this case, the contractor makes the connection to the switch, provides the PoCo with a completition cert. energises the supply (by throwing the switch) and places a seal on it which has an ID + date + signature etc.
Also, with regard to earthing/grounding you cannot change the earthing system in use under any circumstances, only the PoCo can do that and only one connection can be made between the earth and neutral in a PME (protective multiple earthing) system and that is done by the PoCo at a terminal before the meter. You simply leave a customer main earth tail ready for connection.
Oh yeah, if you're doing telephone installations they're rather similar to the United States and Canada. RJ11 is used. However, the wall plates are signifigantly different as they fit UK-style boxes and as telephone ringing voltage is about 75V, they're required to be shuttered so are protected by a gravity activated or spring loaded flap. However, you'll find a pleathra of US-spec'd accessories on the market that don't really comply with this and don' t have shutters. Anything provided by the telco will generally have the shutters present.
for TV installations coax is used, similar specs to the USA. Wall plates are different and you will encounter a "Belling Lee" connector which is similar, but not the same as an F-Connector. F-Connectors tend to only be used for satellite installations.