Electrical & Plumbing

Electrical and plumbing systems are the backbone of any building — invisible yet critically important for comfort, safety, and property value. At Trading Build Engineering, we approach these systems with engineering precision and years of hands-on experience gained across hundreds of residential and commercial projects in Sofia and the surrounding region.

## Electrical Installations

### Power Distribution (Strong Current)

Bulgaria's electrical infrastructure follows European standards (230V/400V, 50Hz), but many older buildings — particularly Communist-era panel apartment blocks ("panelki") built between 1960-1990 — still have original aluminium wiring that has long exceeded its safe service life. This outdated wiring poses serious fire hazards and cannot handle modern electrical loads from air conditioning, induction cooktops, and EV chargers.

We perform complete rewiring with copper cables (NYM for interior, NYY for supply lines) in compliance with Bulgarian Ordinance No. 4/2010 on electrical installations in buildings, harmonised with IEC 60364. Every circuit is protected by correctly rated MCBs (miniature circuit breakers) and RCDs (residual current devices) mounted in a new consumer unit (distribution board). We design separate circuits for lighting (1.5mm²), general outlets (2.5mm²), and high-power appliances such as ovens (4-6mm²), water heaters, washing machines, and air conditioning units.

### Low-Voltage & Data Cabling

Modern homes require robust data infrastructure. We install structured cabling (Cat.6/Cat.6a UTP) for gigabit networking, coaxial cable (RG6) for TV distribution, and dedicated conduit runs for CCTV, intercom, and alarm systems. Low-voltage cables are always run in separate conduits from power cables to prevent electromagnetic interference — a detail that less experienced contractors often overlook.

### Lighting Design

We create comprehensive lighting plans combining ambient, accent, and task lighting for every room. We prepare mounting points for recessed LED panels, LED strip channels, wall sconces, and pendant fixtures. For clients who want atmosphere control, we install dimmers and scene controllers compatible with KNX, Zigbee, or Wi-Fi-based smart home platforms.

### Smart Home Pre-Wiring

The most cost-effective time to prepare for a smart home is during renovation — retrofitting later is far more expensive and disruptive. We run additional control wires to every switch and outlet location, prepare cable routes for motorised blinds and curtains, multi-room audio, centralised HVAC control, and motion/presence sensors. Even if you are not ready for full automation today, having the wiring in place keeps your options open.

## Plumbing Installations

### Water Supply Replacement

Older Bulgarian buildings typically have galvanised steel water pipes that corrode internally over decades, reducing flow, discolouring water, and eventually developing leaks. We replace these with modern PPR (polypropylene random copolymer) or PEX (cross-linked polyethylene) piping systems. PPR pipes are thermally welded, creating leak-proof monolithic joints with a 50+ year lifespan. PEX with press fittings is ideal for manifold (collector) distribution, where each fixture gets its own dedicated pipe from a central manifold — this allows individual shut-off without affecting the rest of the system.

We install isolation valves at strategic points (main entry, before every fixture, before the water meter) and pressure-reducing valves when incoming pressure exceeds 4 bar, protecting your fixtures and appliances from premature wear.

### Drainage & Sewage

We build drainage branches using PVC or PP pipes with appropriate diameters (32mm for basins, 50mm for baths and showers, 110mm for toilets) and correct gradients (2-3% for 50mm, 1-2% for 110mm). Access panels are installed at key points for future maintenance. Where sanitary facilities are located below the main sewer line, we install macerator pumps or sewage lifting stations.

### Bathroom Plumbing

Our complete bathroom renovation encompasses demolition of old finishes, multi-layer waterproofing (liquid membrane plus sealing tape at all joints — the single most critical step that prevents costly water damage), new supply and drain piping, floor drain installation, and final fitting of sanitaryware, mixers, shower enclosures, and bathtubs.

### Kitchen Plumbing

We prepare water supply and drainage connections for sinks, dishwashers, and refrigerators with ice makers. We install anti-siphon valves, quick-access isolation valves, and braided stainless-steel flexible connectors. For island kitchen configurations, supply and drainage pipes are routed through the floor slab before screed is poured.

### Underfloor Heating (Hydronic)

We install hydronic underfloor heating systems using PEX or PE-RT pipes laid on insulation boards with fixing studs, connected to manifolds with flow meters and thermostatic heads. Hydronic underfloor heating delivers even warmth across the entire floor surface and is 20-30% more efficient than radiator systems. It pairs optimally with low-temperature heat sources such as heat pumps or condensing boilers — increasingly popular in Bulgaria's drive toward energy efficiency.

### Radiator & Heating Installation

For conventional radiator systems, we install aluminium, steel panel, or bimetallic radiators sized according to each room's heat-loss calculations. Every radiator is fitted with a thermostatic radiator valve (TRV) for individual room temperature control, helping reduce energy consumption by up to 15%.

## Standards & Certification

All electrical work complies with Bulgarian Ordinance No. 4/2010 and the BDS HD 60364 standard series (equivalent to IEC 60364). Plumbing installations conform to Ordinance No. 4/2005 on building water supply and drainage systems.

Upon completion, we provide: - Insulation resistance test report - Earth fault loop impedance test report - Pressure test certificate for water supply piping - As-built drawings of all concealed installations

These documents are mandatory for occupancy permits and invaluable for future renovations or property sales. Unlike many contractors who skip this paperwork, we consider proper documentation an integral part of every project.