It depends strictly on the UL/CE Zone Rating:

• Zone 0/1 (Inside tub/ shower rim):​ Only fixtures rated IP67 (Submersible)​ or IP68​ are permitted. Traditional chandeliers are NEVER​ allowed here.
  
• Zone 2 (Above the tub, outside splash zone):​ Fixtures must be at least IP44 (Splash Proof).
  
• Critical Clearance:​ Even with an IP44 rating, the bottom of the fixture must be at least 8 feet (2.4m)​ above the highest point of the tub rim to comply with NEC (National Electrical Code) and UK/EU regulations.

Size determines function:

• Above Vanity:​ Width should be 75% to 80%​ of the mirror's width. This prevents "tunnel vision" and ensures even facial lighting.
  
• Above Tub:​ Diameter should be 50% to 60%​ of the tub's length. This creates a focal point without overwhelming the space.
  
• Height Rule:​ Hang the bottom 30-36 inches (76-91 cm)​ above the vanity counter, or 8 feet (2.4m)​ above the tub deck.

This is a common design flaw. To avoid shadows under the chin and eyes:

• Vertical Layering:​ Never rely solely on a ceiling chandelier for makeup or shaving. Combine it with vertical sconces​ on either side of the mirror (at eye level, 60-66 inches AFF).
  
• Shade Direction:​ Choose a chandelier with downward-facing shades​ or frosted diffusers​ to direct light onto the face, not up onto the ceiling.

Bathrooms are high-humidity environments. We combat this by:

• Using Marine-Grade Stainless Steel (316)​ or Brass​ for coastal/high-steam bathrooms to prevent rust.
  
• Applying Anti-Corrosion Nano-Coatings​ to all metal finishes.
  
• Using K9 Crystal or Tempered Glass​ that can withstand rapid temperature changes (thermal shock) without cracking.
  
• Pro Tip:​ Always run the exhaust fan during showers to minimize moisture buildup on the fixture.