Some interesting guidance on candles, including the importance that they not obscure other ritual action:
§ 92 § Candles, which are signs of reverence and festivity, “are to be used at every liturgical service.(GIRM 307) The living flame of the candle, symbolic of the risen Christ, reminds people that in baptism they are brought out of darkness into God’s marvelous light.(1t 2:9) For the celebration of the Eucharist it is appropriate to carry candles in the entrance procession and during the procession with the Book of the Gospels.(GIRM 117) At least two candles are placed near the altar in the sanctuary area. If there is a lack of space, they may be placed on the altar. Four or six candles may be used for the celebration of Mass and for exposition of the Blessed Sacrament. If the bishop of the diocese celebrates, seven candles may be used. Candles placed in floor-standing bases or on the altar should be arranged so they do not obscure the view of the ritual action in the sanctuary, especially the action at the altar.
§ 93 § Candles for liturgical use should be made of a material that provides “a living flame without being smoky or noxious.” To safeguard “authenticity and the full symbolism of light,” electric lights as a substitute for candles are not permitted.(CDWDS Notitiae 10:80 (1974), no. 4)
How many parishes use candles in the entrance procession? How many use more than two for the altar, or more than four for Eucharistic exposition?
And no electric lights to replace candles? Whew!
All texts from Built of Living Stones are copyright © 2000, United States Conference of Catholic Bishops, Inc. All rights reserved. Used with permission.
Catholic Sensibility 
Technically, the prohibition on electric candles only extends to candles for liturgical use, not devotional votives that are left “burning”. I suspect this very deliberately written to accommodate that distinction.
I am not permitted to use real candles for a communion service at a nursing home because a number of residents are on oxygen. I use wax electric candles which look like the real thing.
EJ Mahar
And, since this document is about the furnishing of churches, that sensible safety requirement is not a problem.